Spain · Madrid Completed: Apr 21, 2026 23:01 UTCMobile 375 × 812
Desktop 1440 × 900
Score: 72 / 100
Based on 8 categories, 0 sections
Decent speed, but optimizing further could improve engagement.
Several missing protections leave your users and data exposed.
Several issues make your site difficult for assistive technology users.
Well-optimized for search — your content is discoverable.
Good server performance with room for optimization.
Mostly compliant — a few items need attention.
Missing metadata means poor previews on social media and search.
Heavier than average — reducing page weight saves energy and bandwidth.
The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.
Weights reflect general web best practices. Individual needs may differ.
Content-Security-Policy header is missing
Security gaps expose your site and users to attacks, eroding trust.
No Content-Security-Policy header found
Security gaps expose your site and users to attacks, eroding trust.
Page weighs 6.4 MB (4.7 MB transferred)
Performance issues directly impact user engagement and conversion rates.
2 link(s) with no accessible text
Accessibility issues exclude users with disabilities — up to 15% of your potential audience.
8 image-only link(s) without alt text
Accessibility issues exclude users with disabilities — up to 15% of your potential audience.
High impact, low effort — start here.
High impact, requires investment.
Small gains, minimal effort.
Nothing in this quadrant — good news.
Low impact, high effort — do last.
Nothing in this quadrant — good news.
[](https://beavercheck.com/results/7be8a028-aad8-4bb1-8afd-ea4e030bce7b)<a href="https://beavercheck.com/results/7be8a028-aad8-4bb1-8afd-ea4e030bce7b"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Fucm.es" alt="BeaverCheck Score"></a>https://beavercheck.com/badge?url=https%3A%2F%2Fucm.esThis badge auto-updates with your latest scan result.
Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. Your LCP of 7.6s exceeds Google's 2.5s 'Good' threshold and the 1 performance issue below directly contributes to it. Addressing the critical issues below would have the most immediate impact on your user trust.
8 barrier(s) likely increasing bounce by ~30%.
Page takes 7.6s to load
+12% bounceUsers abandon at ~3s — you're 5.1s over the 2.5s threshold
Fix: Optimize render-blocking resources, preload the hero image, and compress images
No HSTS header
+1% bounceReturning visitors are briefly exposed to downgrade attacks on first request
Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains
No Content-Security-Policy header
+1% bounceHigher XSS blast radius — one compromised script can exfiltrate the checkout form
Fix: Ship a reporting-only CSP first, then enforce once violations are clean
Layout shifts during page load
+3% bounceContent movement causes mis-clicks on CTAs and form fields
Fix: Add width/height to images; reserve space for late-loading embeds
No Open Graph tags
+2% bounceLinks shared on LinkedIn / Slack / Facebook show bare URLs — referral clicks drop
Fix: Add og:title, og:description, og:image, og:url to the page head
No structured data
+2% bounceNo rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices
Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)
No skip-to-content link
+1% bounceKeyboard and screen-reader users must tab through the entire header on every page
Fix: Add a visible-on-focus <a href="#main">Skip to content</a> as the first focusable element
3 broken link(s) on the page
+5% bounceClicks land on 404s — trust drops and the session often ends
Fix: Fix or remove the broken destinations surfaced on the Content tab
Preliminary CRO audit — each barrier links to the tab with detailed analysis.
€330 investment → €4,697/month returns + EUR 120,500,000 risk avoided
€330
6h · 5 findings
€4,697 /mo
~€56,366 / year
EUR 120,500,000
if kept compliant
€55 — in quick wins — start here for the fastest payback
Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.
6.0 developer hours at €55/hr
Based on Spain rates (€55/hr)
Start here for the best return on investment
€10,041,668 / month at risk
~€120,500,013 / year if left unfixed
€120,500,000
+6 more
€1.09 /mo
14662.6 MB/mo × 0.074 EUR/GB
Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.
Unique monthly visitors from your analytics
Purchases, signups, or key actions
Optional — for revenue estimation
more engaged visitors from reduced bounce
Fix 5 critical issues to capture this value
Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.
Your site's LCP: → estimated after fixes.
These are estimates based on industry research — actual results vary
Your data stays in your browser — nothing is sent to our servers
Thanks for your feedback!
We'll use a cached audit if available, or offer to scan.
Industry-standard audits powered by Google Lighthouse.
Key metrics that affect user experience.
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.83 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
7.62 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
158 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.210
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.69 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
13.59 s
Audit breakdown by category with detailed findings.
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.
Performance issues directly impact user engagement and conversion rates.
Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling
Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.
Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.
Source: Google web.dev / Lighthouse
3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.
Performance issues directly impact user engagement and conversion rates.
Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.
Performance issues directly impact user engagement and conversion rates.
Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size
Performance issues directly impact user engagement and conversion rates.
| URL | Resource Size | Est Savings | |
|---|---|---|---|
Competiciones deportivas article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/competiciones/?ver= | 495.1 KiB | 440.7 KiB |
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_152868/_header_img/_229233.png | 397.5 KiB | 386.5 KiB |
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … article.item > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/concurso-primavera-matematicas-2026/?ver=n | 288.1 KiB | 246.3 KiB |
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_152798/_header_img/_229128.png | 250.8 KiB | 240.4 KiB |
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_149996/_header_img/_224396.png | 127.5 KiB | 117.3 KiB |
Complutense Saludable article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/download/?ver=m | 75.2 KiB | 71.1 KiB |
Deporte UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/deporte-2/?ver=m | 61.6 KiB | 58.9 KiB |
HR Excellence in Research ul > li > a > img | ucm.es/themes/ucm24/media/img/hrs4r.png | 57.0 KiB | 56.7 KiB |
¡Inscríbete! article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/jornadas-para-familias-2026-pequena/?ver=m | 50.4 KiB | 43.6 KiB |
Unidad de Cultura Científica UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/foto-portada-ucm-259-x-175-px/?ver=m | 46.2 KiB | 43.0 KiB |
Cultura Complutense article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m | 44.7 KiB | 42.0 KiB |
Consulta de resultados provisionales article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/elecciones-claustro26/?ver=m | 46.9 KiB | 40.2 KiB |
Fundación Complutense article > figure.n_img > a > img | /ext/apps/file/news/imagen-página-web-miniatura-ucmweb-... | 42.3 KiB | 38.0 KiB |
Investigación UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/investigacion/?ver=m | 40.7 KiB | 37.9 KiB |
Prevención de Riesgos Laborales article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/web-bn-pq-prl-01-262x200/?ver=m | 38.7 KiB | 32.0 KiB |
Elecciones 2026: procesos en curso article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/2claustro-universitario26/?ver=m | 34.1 KiB | 27.3 KiB |
Logo div.didomi-popup-container > div.didomi-popup-view > div.didomi-popup-notice-logo-container > img.didomi-popup-notice-logo | www.ucm.es/themes/ucm16/media/img/logo.png | 21.8 KiB | 17.5 KiB |
UCM Directo section#eventos > header > a > img | ucm.es/themes/ucm24/media/img/ucm-directo.png | 13.3 KiB | 12.4 KiB |
Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading
Performance issues directly impact user engagement and conversion rates.
HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.
Performance issues directly impact user engagement and conversion rates.
Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
Performance issues directly impact user engagement and conversion rates.
Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Duration |
|---|---|---|
| ucm.es/themes/ucm24/css/ucm_home.css?ft=20260421140505 | 5.8 KiB | 606 ms |
| ucm.es/themes/ucm24/css/menu_3.css?ft=20260421140504 | 2.0 KiB | 155 ms |
| ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505 | 12.0 KiB | 756 ms |
| ucm.es/themes/ucm24/css/ucm.css?ft=20260421140505 | 6.7 KiB | 606 ms |
| ucm.es/themes/ucm24/css/ucm-theme.css?ft=20260421140505 | 2.2 KiB | 455 ms |
| ucm.es/themes/ucm24/css/font-awesome.min.css | 9.3 KiB | 756 ms |
| ucm.es/themes/ucm24/css/bootstrap.css | 32.8 KiB | 907 ms |
A long cache lifetime can speed up repeat visits to your page. Learn more about caching.
Performance issues directly impact user engagement and conversion rates.
| Request | Cache TTL | Transfer Size |
|---|---|---|
| /dc628592-8975-46a5-82c3-2fb34d165e56/loader.js?target=uc... | 7200.0 s | 29.7 KiB |
Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.
Performance issues directly impact user engagement and conversion rates.
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS
Performance issues directly impact user engagement and conversion rates.
| Element | Layout shift score |
|---|---|
¡Inscríbete!
Prevención de Riesgos Laborales body.didomi-popup-open > main#portada > div.news-flex > section#subzona_2_1 | 0.192 |
In our web pages we use cookies and other similar technologies of our own and o… div#didomi-host > div.notranslate > div#didomi-popup > div.didomi-exterior-border | 0.016 |
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … div#carouselUcm > div.carousel-inner > article.item > div.news1_txt | 0.001 |
Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.
Performance issues directly impact user engagement and conversion rates.
The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.
Performance issues directly impact user engagement and conversion rates.
Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| ucm.es/themes/ucm24/css/bootstrap.css | 32.4 KiB | 30.6 KiB |
| 16.6 KiB | 14.2 KiB | |
| ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505 | 11.5 KiB | 11.5 KiB |
Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.
Multi-megabyte JavaScript bundles delay every interactive feature on the page.
This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.
Source: Google web.dev / Lighthouse
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.googletagmanager.com/gtag/js?id=G-65GWBF2XN6&cx=c>m=4e64h1 | 155.5 KiB | 66.9 KiB |
| www.googletagmanager.com/gtag/js?id=G-6XY0QFTRLR | 157.7 KiB | 63.5 KiB |
| /sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.... | 101.3 KiB | 54.5 KiB |
| ucm.es/themes/ucm24/js/jquery.min.js | 40.4 KiB | 23.8 KiB |
Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache
Performance issues directly impact user engagement and conversion rates.
| Failure reason | Failure type |
|---|---|
| Pages with cache-control:no-store header cannot enter back/forward cache. | Actionable |
| Pages whose main resource has cache-control:no-store cannot enter back/forward cache. | Not actionable |
| Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header. | Not actionable |
Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| ucm.es/themes/ucm24/css/bootstrap.css | 32.8 KiB | 5.5 KiB |
| ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505 | 12.0 KiB | 2.5 KiB |
Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| ucm.es/themes/ucm24/js/bootstrap.js | 21.3 KiB | 7.3 KiB |
Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.
Performance issues directly impact user engagement and conversion rates.
Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions
Performance issues directly impact user engagement and conversion rates.
| URL | |
|---|---|
HR Excellence in Research ul > li > a > img | ucm.es/themes/ucm24/media/img/hrs4r.png |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-informacion.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-transparencia.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-sede-electronica.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-becas-y-ayudas.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-perfil-del-contratante.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-biblioteca.svg |
ul.di_bloque2 > li > a > img ul.di_bloque2 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-campus-virtual.svg |
ul.di_bloque2 > li > a > img ul.di_bloque2 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-online.svg |
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … article.item > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/concurso-primavera-matematicas-2026/?ver=n |
Consulta de resultados provisionales article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/elecciones-claustro26/?ver=m |
Elecciones 2026: procesos en curso article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/2claustro-universitario26/?ver=m |
¡Inscríbete! article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/jornadas-para-familias-2026-pequena/?ver=m |
Prevención de Riesgos Laborales article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/web-bn-pq-prl-01-262x200/?ver=m |
Universidad Complutense de Madrid div#cabecera > div#logo > a > img | ucm.es/themes/ucm24/media/img/logo.svg |
Logo div.didomi-popup-container > div.didomi-popup-view > div.didomi-popup-notice-logo-container > img.didomi-popup-notice-logo | www.ucm.es/themes/ucm16/media/img/logo.png |
Una Europa ul > li > a > img | ucm.es/themes/ucm24/media/img/una-europa.svg |
Universidades Españolas con Ucrania ul > li > a > img | ucm.es/themes/ucm24/media/img/ucrania.png |
Tribuna Complutense ul.enlaces-noticias > li > a > img | ucm.es/themes/ucm24/media/img/ucm-tribuna-complutense.svg |
More information about the performance of your application. These numbers don't directly affect the Performance score.
These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.
Some ARIA parent roles must contain specific child roles to perform their intended accessibility functions. Learn more about roles and required children elements.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … div.news-flex > section#zona_1_3 > div#carouselUcm > div.carousel-inner |
When an input field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about input field labels.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … div.news-flex > section#zona_1_3 > div#carouselUcm > div.carousel-inner |
These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.
Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. Learn more about heading order.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … div.carousel-inner > article.item > div.news1_txt > h3 |
These are opportunities to improve keyboard navigation in your application.
Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Defensora Universitaria li > ul > li > a |
Inspección de Servicios li > ul > li > a |
Fundación General nav#pie_1 > ul > li#75 > a |
Universia España nav#pie_1 > ul > li#12 > a |
Empleo UCM nav#pie_1 > ul > li#175 > a |
Alquiler de espacios nav#pie_1 > ul > li#1206 > a |
Parque Científico nav#pie_1 > ul > li#3197 > a |
Sugerencias y Quejas nav#pie_1 > ul > li#1361 > a |
Localización y contacto nav#pie_contacto > ul > li > a |
Aviso Legal nav#pie_contacto > ul > li > a |
Protección de datos nav#pie_contacto > ul > li > a |
RSS nav#pie_contacto > ul > li > a |
These items highlight common accessibility best practices.
Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.
Performance issues directly impact user engagement and conversion rates.
| URL | Aspect Ratio (Displayed) | Aspect Ratio (Actual) | |
|---|---|---|---|
English ul#lg_items > li > a > img | ucm.es/themes/ucm24/media/img/banderas/en.png | 20 x 20 (1.00) | 30 x 20 (1.50) |
Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.
Performance issues directly impact user engagement and conversion rates.
| URL | Displayed size | Actual size | Expected size | |
|---|---|---|---|---|
English ul#lg_items > li > a > img | ucm.es/themes/ucm24/media/img/banderas/en.png | 20 x 20 | 30 x 20 | 30 x 30 |
These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.
Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable
Performance issues directly impact user engagement and conversion rates.
| Uncrawlable Link |
|---|
main#portada > div.news-plus > section#eventos > a.ev-left main#portada > div.news-plus > section#eventos > a.ev-left |
main#portada > div.news-plus > section#eventos > a.ev-right main#portada > div.news-plus > section#eventos > a.ev-right |
To appear in search results, crawlers need access to your app.
Industry-standard audits powered by Google Lighthouse. — Desktop
Key metrics that affect user experience. — Desktop
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
443 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.82 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
0 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.038
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
838 ms
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
1.83 s
Audit breakdown by category with detailed findings.
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.
Performance issues directly impact user engagement and conversion rates.
Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling
Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.
Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.
Source: Google web.dev / Lighthouse
3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.
Performance issues directly impact user engagement and conversion rates.
A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.
Performance issues directly impact user engagement and conversion rates.
Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size
Performance issues directly impact user engagement and conversion rates.
| URL | Resource Size | Est Savings | |
|---|---|---|---|
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_152868/_header_img/_229233.png | 397.5 KiB | 393.9 KiB |
Competiciones deportivas article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/competiciones/?ver= | 495.1 KiB | 392.4 KiB |
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_152137/_header_img/_228735.png | 393.0 KiB | 389.3 KiB |
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_152798/_header_img/_229128.png | 250.8 KiB | 247.9 KiB |
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … article.item > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/concurso-primavera-matematicas-2026/?ver=n | 288.1 KiB | 233.6 KiB |
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_152086/_header_img/_228385.jpe | 192.9 KiB | 189.7 KiB |
li > div.evento > figure > img li > div.evento > figure > img | eventos.ucm.es/_files/_event/_149996/_header_img/_224396.png | 127.5 KiB | 124.5 KiB |
Complutense Saludable article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/download/?ver=m | 75.2 KiB | 67.9 KiB |
HR Excellence in Research ul > li > a > img | ucm.es/themes/ucm24/media/img/hrs4r.png | 57.0 KiB | 56.9 KiB |
Deporte UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/deporte-2/?ver=m | 61.6 KiB | 53.7 KiB |
¡Inscríbete! article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/jornadas-para-familias-2026-pequena/?ver=m | 50.4 KiB | 42.0 KiB |
Unidad de Cultura Científica UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/foto-portada-ucm-259-x-175-px/?ver=m | 46.2 KiB | 38.8 KiB |
Consulta de resultados provisionales article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/elecciones-claustro26/?ver=m | 46.9 KiB | 38.4 KiB |
Cultura Complutense article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m | 44.7 KiB | 36.8 KiB |
Fundación Complutense article > figure.n_img > a > img | /ext/apps/file/news/imagen-página-web-miniatura-ucmweb-... | 42.3 KiB | 34.9 KiB |
Investigación UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/investigacion/?ver=m | 40.7 KiB | 32.7 KiB |
Prevención de Riesgos Laborales article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/web-bn-pq-prl-01-262x200/?ver=m | 38.7 KiB | 30.3 KiB |
Elecciones 2026: procesos en curso article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/2claustro-universitario26/?ver=m | 34.1 KiB | 25.5 KiB |
Logo div.didomi-popup-container > div.didomi-popup-view > div.didomi-popup-notice-logo-container > img.didomi-popup-notice-logo | www.ucm.es/themes/ucm16/media/img/logo.png | 21.8 KiB | 20.1 KiB |
UCM Directo section#eventos > header > a > img | ucm.es/themes/ucm24/media/img/ucm-directo.png | 13.3 KiB | 12.9 KiB |
Universidades Españolas con Ucrania ul > li > a > img | ucm.es/themes/ucm24/media/img/ucrania.png | 6.7 KiB | 6.5 KiB |
Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading
Performance issues directly impact user engagement and conversion rates.
HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.
Performance issues directly impact user engagement and conversion rates.
Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
Performance issues directly impact user engagement and conversion rates.
Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Duration |
|---|---|---|
| ucm.es/themes/ucm24/css/menu_3.css?ft=20260421140504 | 2.0 KiB | |
| ucm.es/themes/ucm24/css/ucm_home.css?ft=20260421140505 | 5.8 KiB | 133 ms |
| ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505 | 12.0 KiB | 175 ms |
| ucm.es/themes/ucm24/css/ucm.css?ft=20260421140505 | 6.7 KiB | 133 ms |
| ucm.es/themes/ucm24/css/font-awesome.min.css | 9.3 KiB | 175 ms |
| ucm.es/themes/ucm24/css/ucm-theme.css?ft=20260421140505 | 2.2 KiB | 133 ms |
| ucm.es/themes/ucm24/css/bootstrap.css | 32.7 KiB | 175 ms |
A long cache lifetime can speed up repeat visits to your page. Learn more about caching.
Performance issues directly impact user engagement and conversion rates.
| Request | Cache TTL | Transfer Size |
|---|---|---|
| /dc628592-8975-46a5-82c3-2fb34d165e56/loader.js?target=uc... | 7200.0 s | 29.7 KiB |
Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.
Performance issues directly impact user engagement and conversion rates.
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| ucm.es/themes/ucm24/js/bootstrap.js | 21.3 KiB | 7.3 KiB |
Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| ucm.es/themes/ucm24/css/bootstrap.css | 32.2 KiB | 30.3 KiB |
| 16.6 KiB | 14.3 KiB | |
| ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505 | 11.5 KiB | 11.5 KiB |
Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.
Multi-megabyte JavaScript bundles delay every interactive feature on the page.
This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.
Source: Google web.dev / Lighthouse
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.googletagmanager.com/gtag/js?id=G-65GWBF2XN6&cx=c>m=4e64h1 | 155.5 KiB | 66.9 KiB |
| www.googletagmanager.com/gtag/js?id=G-6XY0QFTRLR | 157.7 KiB | 63.5 KiB |
| /sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.... | 101.3 KiB | 54.5 KiB |
| ucm.es/themes/ucm24/js/jquery.min.js | 40.4 KiB | 24.1 KiB |
Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache
Performance issues directly impact user engagement and conversion rates.
| Failure reason | Failure type |
|---|---|
| Pages with cache-control:no-store header cannot enter back/forward cache. | Actionable |
| Pages whose main resource has cache-control:no-store cannot enter back/forward cache. | Not actionable |
| Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header. | Not actionable |
Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| ucm.es/themes/ucm24/css/bootstrap.css | 32.7 KiB | 5.5 KiB |
| ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505 | 12.0 KiB | 2.5 KiB |
Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.
Performance issues directly impact user engagement and conversion rates.
Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions
Performance issues directly impact user engagement and conversion rates.
| URL | |
|---|---|
HR Excellence in Research ul > li > a > img | ucm.es/themes/ucm24/media/img/hrs4r.png |
Competiciones deportivas article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/competiciones/?ver= |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-informacion.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-transparencia.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-sede-electronica.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-becas-y-ayudas.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-perfil-del-contratante.svg |
ul.di_bloque1 > li > a > img ul.di_bloque1 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-biblioteca.svg |
ul.di_bloque2 > li > a > img ul.di_bloque2 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-campus-virtual.svg |
ul.di_bloque2 > li > a > img ul.di_bloque2 > li > a > img | ucm.es/themes/ucm24/media/img/iconos/ucm-online.svg |
Fundación Complutense article > figure.n_img > a > img | /ext/apps/file/news/imagen-página-web-miniatura-ucmweb-... |
Complutense Saludable article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/download/?ver=m |
Investigación UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/investigacion/?ver=m |
Cultura Complutense article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m |
Deporte UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/deporte-2/?ver=m |
Unidad de Cultura Científica UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/foto-portada-ucm-259-x-175-px/?ver=m |
Universidad Complutense de Madrid div#cabecera > div#logo > a > img | ucm.es/themes/ucm24/media/img/logo.svg |
Logo div.didomi-popup-container > div.didomi-popup-view > div.didomi-popup-notice-logo-container > img.didomi-popup-notice-logo | www.ucm.es/themes/ucm16/media/img/logo.png |
Una Europa ul > li > a > img | ucm.es/themes/ucm24/media/img/una-europa.svg |
Universidades Españolas con Ucrania ul > li > a > img | ucm.es/themes/ucm24/media/img/ucrania.png |
Tribuna Complutense ul.enlaces-noticias > li > a > img | ucm.es/themes/ucm24/media/img/ucm-tribuna-complutense.svg |
More information about the performance of your application. These numbers don't directly affect the Performance score.
These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.
Some ARIA parent roles must contain specific child roles to perform their intended accessibility functions. Learn more about roles and required children elements.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … div.news-flex > section#zona_1_3 > div#carouselUcm > div.carousel-inner |
When an input field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about input field labels.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … div.news-flex > section#zona_1_3 > div#carouselUcm > div.carousel-inner |
These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.
Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. Learn more about heading order.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … div.carousel-inner > article.item > div.news1_txt > h3 |
These are opportunities to improve keyboard navigation in your application.
Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Defensora Universitaria li > ul > li > a |
Inspección de Servicios li > ul > li > a |
These items highlight common accessibility best practices.
Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.
Performance issues directly impact user engagement and conversion rates.
| URL | Aspect Ratio (Displayed) | Aspect Ratio (Actual) | |
|---|---|---|---|
English ul#lg_items > li > a > img | ucm.es/themes/ucm24/media/img/banderas/en.png | 20 x 20 (1.00) | 30 x 20 (1.50) |
Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.
Performance issues directly impact user engagement and conversion rates.
| URL | Displayed size | Actual size | Expected size | |
|---|---|---|---|---|
Investigación UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/investigacion/?ver=m | 436 x 238 | 300 x 164 | 436 x 238 |
Deporte UCM article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/deporte-2/?ver=m | 436 x 237 | 300 x 163 | 436 x 237 |
Cultura Complutense article > figure.n_img > a > img | www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m | 436 x 237 | 300 x 163 | 436 x 237 |
These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.
Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable
Performance issues directly impact user engagement and conversion rates.
| Uncrawlable Link |
|---|
main#portada > div.news-plus > section#eventos > a.ev-left main#portada > div.news-plus > section#eventos > a.ev-left |
main#portada > div.news-plus > section#eventos > a.ev-right main#portada > div.news-plus > section#eventos > a.ev-right |
To appear in search results, crawlers need access to your app.
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