Skip to content
https://citizensadvice.org.uk

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
94
GRADE
A
FIX
2
REVIEW
1
PASS
12
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
96
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

2.05 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

2.43 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

21 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.004

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

2.05 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.

2.69 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
17
12 PASS 1 REVIEW 2 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (145.3 KiB of 145.6 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
146 KB transferred, 13 requests
PASS
146 KB transferred, 13 requests
Info::
Page weighs 439 KB (146 KB transferred)
Info::
13 HTTP requests
Info::
Estimated 0.03 g CO2 per page load
146 KB / 2.4 MB budget
146 KB transferred
13 requests
0.03 g CO2 per page load
JavaScript 58.0 KiB 40%
Fonts 33.0 KiB 23%
CSS 24.1 KiB 17%
Other 17.1 KiB 12%
HTML 8.6 KiB 6%
Images 4.8 KiB 3%
0 2.4 MB 4.9 MB
Under budget
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A
Image Optimization
2 images, 0 KB saveable
PASS
2 images, 0 KB saveable
Warning::
https://www.fundraisingregulator.org.uk/fr-badge/6... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
2 images 5 KB
0 oversized -0 KB
1 legacy format
1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

A+
JS Execution Cost
370ms total JS execution
PASS
370ms total JS execution
Info::
https://www.citizensadvice.org.uk/: 175ms CPU time
Info::
Unattributable: 102ms CPU time
Info::
https://www.citizensadvice.org.uk/assets/polyfill-...: 92ms CPU time
Warning::
Third-party scripts: 370ms (100% of total)

Main Thread Breakdown

Style & Layout 31% Other 29% Script Evaluation 23% Script Parsing & Compilation 8% Rendering 6% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
https://www.citizensadvice.org.uk/175ms5ms1ms3rd
Unattributable102ms6ms0ms3rd
https://www.citizensadvice.org.uk/assets/polyfill-888987f7030a40d2ba92963038d6e451452f337a36e1688ebb55057600318afe.js92ms62ms29ms3rd
A+
Font Loading
2 fonts (33 KB)
PASS
2 fonts (33 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

33 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 2.1 s LCP 2.4 shttps://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-700-c12de74c75388b99217911061da4f485071392d528338b1f7052007ac0eb396b.woff2open-sans-v26-latin-700... https://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-700-c12de74c75388b99217911061da4f485071392d528338b1f7052007ac0eb396b.woff2 — 16.3 KiB — 6 ms — font-display: swaphttps://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-regular-2d8f2b8387a095f3e77a79e59b6026ce3ec5a3f02a62ffafd652496d0e331006.woff2open-sans-v26-latin-reg... https://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-regular-2d8f2b8387a095f3e77a79e59b6026ce3ec5a3f02a62ffafd652496d0e331006.woff2 — 16.7 KiB — 6 ms — font-display: swap
open-sans-v26-latin-700... woff2 swap
Size 16 KB
Load time 6 ms
Start 219 ms
Risk FOUT — text flashes from fallback to web font
open-sans-v26-latin-reg... woff2 swap
Size 17 KB
Load time 6 ms
Start 220 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)
A+
JS Bundles
5 scripts, 0 KB unused
PASS
5 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.citizensadvice.org.uk/assets/citizens_advice_cookie_preferences/application-190ad337d2da8b75bdbac17369f1a530173572d48ab39634aed143910b4c0421.js2 KB—✓3rd
https://www.citizensadvice.org.uk/assets/polyfill-888987f7030a40d2ba92963038d6e451452f337a36e1688ebb55057600318afe.js47 KB—✓3rd
https://www.citizensadvice.org.uk/assets/public-homepage-e57be2fa2dacb646332889557bf0efa9c9e79d68011bbe433a19a853b306492d.js5 KB—✓3rd
https://www.citizensadvice.org.uk/assets/connect-prod-training-13cda6c3e135e8130e366f13aabfaa5c6b1856b4110705654a0715f8a97b6cf1.js2 KB—✓3rd
https://www.citizensadvice.org.uk/assets/connect-prod-55ea73a6b62b5bf4775792882f06044975a5d6c341392c3561a9b3dc4873a8c7.js2 KB—✓3rd
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A
Page Weight Inventory
13 resources · 146 KB · 0 KB savings available
PASS
13 resources · 146 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 146 KB
Warning::
12 third-party resources (100% of weight)
13 resources · 145.6 KiB · 12 third-party Within 1MB page-weight target
JavaScript 40% · 58.0 KiB
Font 23% · 33.0 KiB
CSS 17% · 24.1 KiB
Image 15% · 21.7 KiB
Document 6% · 8.6 KiB
Other 0% · 250 B
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
13 requests over 369ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 2.1 s LCP 2.4 shttps://citizensadvice.org.uk// https://citizensadvice.org.uk/ — 301 — 250 B — 104 ms — h2https://www.citizensadvice.org.uk/www.citizensadvice.org.uk/ https://www.citizensadvice.org.uk/ — 200 — 8.6 KiB — 53 ms — h2https://www.citizensadvice.org.uk/assets/public-homepage-d37d73d773de021a364144e6ed12a17e57272e01c93f1765d7d577125318350b.csswww.citizensadvice.org.uk/assets/pu... https://www.citizensadvice.org.uk/assets/public-homepage-d37d73d773de021a364144e6ed12a17e57272e01c93f1765d7d577125318350b.css — 200 — 24.1 KiB — 10 ms — h2https://www.citizensadvice.org.uk/assets/citizens_advice_cookie_preferences/application-190ad337d2da8b75bdbac17369f1a530173572d48ab39634aed143910b4c0421.jswww.citizensadvice.org.uk/assets/ci... https://www.citizensadvice.org.uk/assets/citizens_advice_cookie_preferences/application-190ad337d2da8b75bdbac17369f1a530173572d48ab39634aed143910b4c0421.js — 200 — 1.7 KiB — 7 ms — h2https://www.fundraisingregulator.org.uk/fr-badge/6d8352f2-d995-4eea-bb60-a28c2dc8d842/en/blackwww.fundraisingregulator.org.uk/fr-... https://www.fundraisingregulator.org.uk/fr-badge/6d8352f2-d995-4eea-bb60-a28c2dc8d842/en/black — 200 — 4.8 KiB — 103 ms — h3https://www.citizensadvice.org.uk/assets/polyfill-888987f7030a40d2ba92963038d6e451452f337a36e1688ebb55057600318afe.jswww.citizensadvice.org.uk/assets/po... https://www.citizensadvice.org.uk/assets/polyfill-888987f7030a40d2ba92963038d6e451452f337a36e1688ebb55057600318afe.js — 200 — 46.7 KiB — 17 ms — h2https://www.citizensadvice.org.uk/assets/public-homepage-e57be2fa2dacb646332889557bf0efa9c9e79d68011bbe433a19a853b306492d.jswww.citizensadvice.org.uk/assets/pu... https://www.citizensadvice.org.uk/assets/public-homepage-e57be2fa2dacb646332889557bf0efa9c9e79d68011bbe433a19a853b306492d.js — 200 — 4.6 KiB — 16 ms — h2https://www.citizensadvice.org.uk/assets/connect-prod-training-13cda6c3e135e8130e366f13aabfaa5c6b1856b4110705654a0715f8a97b6cf1.jswww.citizensadvice.org.uk/assets/co... https://www.citizensadvice.org.uk/assets/connect-prod-training-13cda6c3e135e8130e366f13aabfaa5c6b1856b4110705654a0715f8a97b6cf1.js — 200 — 2.5 KiB — 13 ms — h2https://www.citizensadvice.org.uk/assets/connect-prod-55ea73a6b62b5bf4775792882f06044975a5d6c341392c3561a9b3dc4873a8c7.jswww.citizensadvice.org.uk/assets/co... https://www.citizensadvice.org.uk/assets/connect-prod-55ea73a6b62b5bf4775792882f06044975a5d6c341392c3561a9b3dc4873a8c7.js — 200 — 2.5 KiB — 14 ms — h2data:image/svg+xml,%3C%3Fxml version='1.0' encoding='UTF-8'%3F%3E%3Csvg xmlns='http://www.w3.org/20…www.w3.org/20… data:image/svg+xml,%3C%3Fxml version='1.0' encoding='UTF-8'%3F%3E%3Csvg xmlns='http://www.w3.org/20… — 200 — 0 B — 0 ms — datahttps://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-700-c12de74c75388b99217911061da4f485071392d528338b1f7052007ac0eb396b.woff2www.citizensadvice.org.uk/assets/ci... https://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-700-c12de74c75388b99217911061da4f485071392d528338b1f7052007ac0eb396b.woff2 — 200 — 16.3 KiB — 6 ms — h2https://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-regular-2d8f2b8387a095f3e77a79e59b6026ce3ec5a3f02a62ffafd652496d0e331006.woff2www.citizensadvice.org.uk/assets/ci... https://www.citizensadvice.org.uk/assets/citizens_advice_components/open-sans-v26-latin-regular-2d8f2b8387a095f3e77a79e59b6026ce3ec5a3f02a62ffafd652496d0e331006.woff2 — 200 — 16.7 KiB — 6 ms — h2https://www.citizensadvice.org.uk/favicon.icowww.citizensadvice.org.uk/favicon.i... https://www.citizensadvice.org.uk/favicon.ico — 200 — 16.9 KiB — 86 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 370ms · 55KB · £4/mo
www.citizensadvice.org.uk
Other
Optional
Execution 175ms
Transfer 9 KB
Monthly Cost £2/mo
Unattributable
Other
Optional
Execution 102ms
Transfer 0 KB
Monthly Cost £1/mo
www.citizensadvice.org.uk
Other
Optional
Execution 92ms
Transfer 47 KB
Monthly Cost £1/mo

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback