Performance
· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
3.02 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
12.15 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
4.19 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.220
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.19 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.
28.48 s
Page Load Progression
FPage Weight BudgetAction5.2 MB transferred, 134 requestsFIX
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction10355ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 1229ms | 139ms | 0ms | 3rd |
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 1103ms | 936ms | 123ms | 3rd |
| https://try.abtasty.com/03d869a33f572dd77e62594449ebd8cb/main.4f8fe8525f40523c4a4c.js | 1054ms | 928ms | 26ms | 3rd |
| https://www.tate.org.uk/ | 1050ms | 18ms | 9ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-WQPJ9H | 918ms | 766ms | 85ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-Q4CTQC82D1&cx=c>m=4e64h1 | 454ms | 348ms | 100ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-4GZRWXM2P8&cx=c>m=4e64h1 | 443ms | 344ms | 54ms | 3rd |
| https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js | 435ms | 227ms | 10ms | 3rd |
| https://www.tate.org.uk/static/js/TateUI.c2ca8065327f.js | 415ms | 255ms | 67ms | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMA.js | 348ms | 284ms | 58ms | 3rd |
Showing top 10 of 26 scripts
FJS BundlesAction52 scripts, 1.2 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 0 KB | 177 KB (49%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 362 KB | 177 KB (49%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js | 362 KB | 177 KB (49%) | ✓ | 3rd |
| https://www.tate.org.uk/static/js/TateUI.c2ca8065327f.js | 138 KB | 103 KB (75%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-Q4CTQC82D1&cx=c>m=4e64h1 | 173 KB | 65 KB (37%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-4GZRWXM2P8&cx=c>m=4e64h1 | 155 KB | 62 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=DC-13274131&cx=c>m=4e64h1 | 129 KB | 60 KB (46%) | ✓ | 3rd |
| https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMA.js | 106 KB | 57 KB (54%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=AW-1012661956&cx=c>m=4e64h1 | 145 KB | 56 KB (39%) | ✓ | 3rd |
| https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js | 102 KB | 56 KB (54%) | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction134 resources · 5.2 MB · 1.2 MB savings availableFIX
~1.2 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 134 resources | 5.2 MiB | ||||||
CImage OptimizationAction41 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
A+Text CompressionAll text resources are compressedPASS
A+Font Loading5 fonts (204 KB)PASS
Web fonts
5
204 KB total
Render-blocking
0
of 5
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
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)
Fixing the unchecked items could save ~51 KB and ~102 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource Hints3 hints, 0 missing preconnectsPASS
Current Resource Hints
3 resource hints configured
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Axis12 Ltd
AHTTP Cachingmax-age=86400 (1 day)PASS
max-age=86400
| Directive | Value | Meaning |
|---|---|---|
| max-age | 86400 | Cache for 1 day |
Network Waterfall134 requests over 2890msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 1229ms | 0 KB | — | £13/mo | Costly |
www.gstatic.com www.gstatic.com | Other | 1103ms | 0 KB | 49% | £11/mo | Costly |
try.abtasty.com try.abtasty.com | Other | 1054ms | 67 KB | 62% | £11/mo | Costly |
www.tate.org.uk www.tate.org.uk | Other | 1050ms | 15 KB | — | £11/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 918ms | 206 KB | 26% | £10/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 454ms | 173 KB | 37% | £5/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 443ms | 155 KB | 40% | £5/mo | Costly |
ajax.googleapis.com ajax.googleapis.com | Other | 435ms | 30 KB | — | £5/mo | Costly |
www.tate.org.uk www.tate.org.uk | Other | 415ms | 138 KB | 75% | £4/mo | Costly |
analytics.tiktok.com analytics.tiktok.com | Other | 348ms | 106 KB | 54% | £4/mo | Costly |
sdk.privacy-center.org sdk.privacy-center.org | Other | 341ms | 54 KB | 38% | £4/mo | Costly |
Facebook Pixel connect.facebook.net | Advertising | 329ms | 97 KB | 33% | £3/mo | Costly |
sdk.privacy-center.org sdk.privacy-center.org | Other | 308ms | 102 KB | 54% | £3/mo | Costly |
Facebook Pixel connect.facebook.net | Advertising | 295ms | 16 KB | — | £3/mo | Costly |
Hotjar script.hotjar.com | Session Replay | 234ms | 57 KB | 66% | £2/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 209ms | 145 KB | 37% | £2/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 208ms | 145 KB | 39% | £2/mo | Costly |
Twitter/X Pixel static.ads-twitter.com | Advertising | 187ms | 13 KB | — | £2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 153ms | 129 KB | 46% | £2/mo | Optional |
s.pinimg.com s.pinimg.com | Other | 129ms | 27 KB | — | £1/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 127ms | 46 KB | — | £1/mo | Optional |
Facebook Pixel connect.facebook.net | Advertising | 94ms | 16 KB | — | £1/mo | Optional |
tags.srv.stackadapt.com tags.srv.stackadapt.com | Other | 92ms | 8 KB | — | £1/mo | Optional |
analytics.tiktok.com analytics.tiktok.com | Other | 74ms | 40 KB | — | £1/mo | Optional |
static.queue-it.net static.queue-it.net | Other | 73ms | 7 KB | — | £1/mo | Optional |
Hotjar static.hotjar.com | Session Replay | 55ms | 6 KB | — | £1/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 1229ms and costs ~£13/month
- www.gstatic.com adds 1103ms and costs ~£11/month
- try.abtasty.com adds 1054ms and costs ~£11/month
- www.tate.org.uk adds 1050ms and costs ~£11/month
- Google Tag Manager adds 918ms and costs ~£10/month
- Google Tag Manager adds 454ms and costs ~£5/month
- Google Tag Manager adds 443ms and costs ~£5/month
- ajax.googleapis.com adds 435ms and costs ~£5/month
- www.tate.org.uk adds 415ms and costs ~£4/month
- analytics.tiktok.com adds 348ms and costs ~£4/month
- sdk.privacy-center.org adds 341ms and costs ~£4/month
- Facebook Pixel adds 329ms and costs ~£3/month
- sdk.privacy-center.org adds 308ms and costs ~£3/month
- Facebook Pixel adds 295ms and costs ~£3/month
- Hotjar adds 234ms and costs ~£2/month
- Google Tag Manager adds 209ms and costs ~£2/month
- Google Tag Manager adds 208ms and costs ~£2/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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
Unattributable takes 1229ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.gstatic.com takes 1103ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
try.abtasty.com takes 1054ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
62% of try.abtasty.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
www.tate.org.uk takes 1050ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 918ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 454ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 443ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
ajax.googleapis.com takes 435ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.tate.org.uk takes 415ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
75% of www.tate.org.uk's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
analytics.tiktok.com takes 348ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of analytics.tiktok.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
sdk.privacy-center.org takes 341ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Facebook Pixel takes 329ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
sdk.privacy-center.org takes 308ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of sdk.privacy-center.org's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Facebook Pixel takes 295ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Hotjar takes 234ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
66% of Hotjar's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Google Tag Manager takes 209ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 208ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev