Skip to content
https://vam.ac.uk

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
84
GRADE
B
FIX
3
REVIEW
4
PASS
6
INFO
2

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

Mobile Desktop
94
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.

876 ms

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

1.47 s

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

17 ms

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

0.001

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

1.05 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.

1.75 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
15
6 PASS 4 REVIEW 3 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 (1.6 MiB of 1.6 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
Page Weight Inventory
Action
43 resources · 1.6 MB · 139 KB savings available
FIX
43 resources · 1.6 MB · 139 KB savings available
Warning::
Page weight 641 KB over 1MB target
Got: 1.6 MB Expected: ≤ 1 MB
Info::
~139 KB of savings available
Warning::
42 third-party resources (100% of weight)
43 resources · 1.6 MiB · 42 third-party 641.3 KiB over 1MB target
Image 53% · 881.0 KiB
JavaScript 22% · 368.8 KiB
Font 11% · 177.7 KiB
Other 10% · 167.6 KiB
CSS 3% · 48.6 KiB
Document 1% · 21.8 KiB

~139.0 KiB of savings available

Remove unused JavaScript: 139.0 KiB
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
Page Weight Budget
Action
1.6 MB transferred, 43 requests
REVIEW
1.6 MB transferred, 43 requests
Info::
Page weighs 4.0 MB (1.6 MB transferred)
Info::
43 HTTP requests
Info::
Estimated 0.34 g CO2 per page load
1.6 MB / 2.4 MB budget
1.6 MB transferred
43 requests
0.34 g CO2 per page load
Images 811.4 KiB 49%
JavaScript 368.8 KiB 22%
Fonts 177.7 KiB 11%
Other 147.2 KiB 9%
Other 69.2 KiB 4%
CSS 44.0 KiB 3%
Other 24.7 KiB 1%
HTML 21.6 KiB 1%
Other 799 B 0%
0 2.4 MB 4.9 MB
Approaching limit
B
Image Optimization
19 images, 0 KB saveable
REVIEW
19 images, 0 KB saveable
Warning::
is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
19 images 811 KB
0 oversized -0 KB
15 legacy format
1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

B
JS Bundles
6 scripts, 139 KB unused
REVIEW
6 scripts, 139 KB unused
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-P24...: 79 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.cookielaw.org/scripttemplates/202510.1...: 60 KB unused (48%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 139 KB
139 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtm.js?id=GTM-P24KW5198 KB79 KB (40%)✓3rd
https://cdn.cookielaw.org/scripttemplates/202510.1.0/otBannerSdk.js123 KB60 KB (48%)✓3rd
https://cdn.cookielaw.org/scripttemplates/otSDKStub.js9 KB—✓3rd
https://www.vam.ac.uk/packs/js/vam-fractal-cdd985373148c42cc3d6.js11 KB—✓3rd
https://www.vam.ac.uk/packs/js/application-9b0a6e0d56041a444b5e.js10 KB—✓3rd
https://cdn.cookielaw.org/scripttemplates/202510.1.0/otTCF.js18 KB—✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

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.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

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

Green Hosting

No green hosting detected

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+
JS Execution Cost
486ms total JS execution
PASS
486ms total JS execution
Info::
Unattributable: 181ms CPU time
Info::
https://www.vam.ac.uk/: 120ms CPU time
Info::
https://cdn.cookielaw.org/scripttemplates/202510.1...: 69ms CPU time
Info::
https://cdn.cookielaw.org/scripttemplates/otSDKStu...: 65ms CPU time
Info::
https://www.googletagmanager.com/gtm.js?id=GTM-P24...: 51ms CPU time
Warning::
Third-party scripts: 486ms (100% of total)

Main Thread Breakdown

Script Evaluation 45% Other 25% Style & Layout 14% Script Parsing & Compilation 7% Parse HTML & CSS 4% Garbage Collection 3% Rendering 3%
ScriptTotalScriptingParse/CompileParty
Unattributable181ms81ms0ms3rd
https://www.vam.ac.uk/120ms4ms1ms3rd
https://cdn.cookielaw.org/scripttemplates/202510.1.0/otBannerSdk.js69ms43ms10ms3rd
https://cdn.cookielaw.org/scripttemplates/otSDKStub.js65ms57ms1ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-P24KW551ms30ms20ms3rd
A+
Font Loading
2 fonts (178 KB)
PASS
2 fonts (178 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

178 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 FCP 876 ms LCP 1.5 shttps://www.vam.ac.uk/fonts/Spiller-Upright-weight-VF-Web-V2.woff2Spiller-Upright-weight-... https://www.vam.ac.uk/fonts/Spiller-Upright-weight-VF-Web-V2.woff2 — 79.1 KiB — 19 ms — font-display: swaphttps://www.vam.ac.uk/fonts/SpillerWidth-Upright-width_weight-VF-Web.woff2SpillerWidth-Upright-wi... https://www.vam.ac.uk/fonts/SpillerWidth-Upright-width_weight-VF-Web.woff2 — 98.6 KiB — 29 ms — font-display: swap
Spiller-Upright-weight-... woff2 swap
Size 79 KB
Load time 19 ms
Start 303 ms
Risk FOUT — text flashes from fallback to web font
SpillerWidth-Upright-wi... woff2 swap
Size 99 KB
Load time 29 ms
Start 303 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+
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
Network Waterfall
43 requests over 819ms
INFO
0 ms 500 ms 1.0 s 1.5 s FCP 876 ms LCP 1.5 shttps://vam.ac.uk// https://vam.ac.uk/ — 301 — 175 B — 111 ms — http/1.1https://www.vam.ac.uk/www.vam.ac.uk/ https://www.vam.ac.uk/ — 200 — 21.6 KiB — 10 ms — h2https://www.vam.ac.uk/assets/application-c50bba875c3aa362ba61ad6702a6df308dfb3678ca885c649138569e328f1608.csswww.vam.ac.uk/assets/application-c5... https://www.vam.ac.uk/assets/application-c50bba875c3aa362ba61ad6702a6df308dfb3678ca885c649138569e328f1608.css — 200 — 44.0 KiB — 7 ms — h2https://cdn.cookielaw.org/scripttemplates/otSDKStub.jscdn.cookielaw.org/scripttemplates/o... https://cdn.cookielaw.org/scripttemplates/otSDKStub.js — 200 — 9.1 KiB — 100 ms — h2https://assets-cdn.vam.ac.uk/2026/04/14/11/22/04/4e5b727e-79a1-419d-8d00-8928b90a0409/1920.jpgassets-cdn.vam.ac.uk/2026/04/14/11/... https://assets-cdn.vam.ac.uk/2026/04/14/11/22/04/4e5b727e-79a1-419d-8d00-8928b90a0409/1920.jpg — 200 — 174.1 KiB — 16 ms — h2https://www.vam.ac.uk/assets/favicon/manifest-3c37297d439cc0a5dc5f02e7b9bd80598c41b60a2346b24f0618ef8eaa72258b.jsonwww.vam.ac.uk/assets/favicon/manife... https://www.vam.ac.uk/assets/favicon/manifest-3c37297d439cc0a5dc5f02e7b9bd80598c41b60a2346b24f0618ef8eaa72258b.json — 200 — 799 B — 7 ms — h2https://www.vam.ac.uk/packs/js/vam-fractal-cdd985373148c42cc3d6.jswww.vam.ac.uk/packs/js/vam-fractal-... https://www.vam.ac.uk/packs/js/vam-fractal-cdd985373148c42cc3d6.js — 200 — 10.6 KiB — 4 ms — h2https://www.vam.ac.uk/packs/js/application-9b0a6e0d56041a444b5e.jswww.vam.ac.uk/packs/js/application-... https://www.vam.ac.uk/packs/js/application-9b0a6e0d56041a444b5e.js — 200 — 9.6 KiB — 3 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-P24KW5www.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-P24KW5 — 200 — 198.3 KiB — 148 ms — h2https://cdn.cookielaw.org/consent/063ed2c5-fa48-4395-bdb3-999b05bd01fd/063ed2c5-fa48-4395-bdb3-999b05bd01fd.jsoncdn.cookielaw.org/consent/063ed2c5-... https://cdn.cookielaw.org/consent/063ed2c5-fa48-4395-bdb3-999b05bd01fd/063ed2c5-fa48-4395-bdb3-999b05bd01fd.json — 200 — 2.4 KiB — 72 ms — h2https://www.vam.ac.uk/assets/vam-sprite-336679439415943192abd08310316502cdd2edb65ff20acfeb4bd8ed7ce9287d.svgwww.vam.ac.uk/assets/vam-sprite-336... https://www.vam.ac.uk/assets/vam-sprite-336679439415943192abd08310316502cdd2edb65ff20acfeb4bd8ed7ce9287d.svg — 200 — 57.9 KiB — 5 ms — h2data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp… — 200 — 0 B — 0 ms — datadata:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C… — 200 — 0 B — 0 ms — datadata:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C… — 200 — 0 B — 0 ms — datadata:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp… — 200 — 0 B — 0 ms — datahttps://assets-cdn.vam.ac.uk/2022/07/18/10/43/04/1d1d02e9-ef6f-4ada-bc85-cc092f656808/640.jpgassets-cdn.vam.ac.uk/2022/07/18/10/... https://assets-cdn.vam.ac.uk/2022/07/18/10/43/04/1d1d02e9-ef6f-4ada-bc85-cc092f656808/640.jpg — 200 — 67.9 KiB — 40 ms — h2https://assets-cdn.vam.ac.uk/2026/04/18/06/34/11/01b8ec10-7eef-497e-b704-a4abfa2ff2ec/320.jpgassets-cdn.vam.ac.uk/2026/04/18/06/... https://assets-cdn.vam.ac.uk/2026/04/18/06/34/11/01b8ec10-7eef-497e-b704-a4abfa2ff2ec/320.jpg — 200 — 35.3 KiB — 47 ms — h2https://assets-cdn.vam.ac.uk/2025/11/20/15/22/58/77c37dbf-e883-4c09-92ed-cf7474716c16/320.jpgassets-cdn.vam.ac.uk/2025/11/20/15/... https://assets-cdn.vam.ac.uk/2025/11/20/15/22/58/77c37dbf-e883-4c09-92ed-cf7474716c16/320.jpg — 200 — 45.4 KiB — 45 ms — h2https://assets-cdn.vam.ac.uk/2022/07/18/10/51/13/e7d3df02-176f-4398-bb56-f47943a77124/320.jpgassets-cdn.vam.ac.uk/2022/07/18/10/... https://assets-cdn.vam.ac.uk/2022/07/18/10/51/13/e7d3df02-176f-4398-bb56-f47943a77124/320.jpg — 200 — 50.2 KiB — 31 ms — h2https://assets-cdn.vam.ac.uk/2024/11/19/13/03/14/dc9ed5b0-0865-434f-9993-90b9cbe21a74/640.jpgassets-cdn.vam.ac.uk/2024/11/19/13/... https://assets-cdn.vam.ac.uk/2024/11/19/13/03/14/dc9ed5b0-0865-434f-9993-90b9cbe21a74/640.jpg — 200 — 48.8 KiB — 49 ms — h2https://vanda-production-assets.s3.amazonaws.com/2026/04/20/08/26/57/0382b05a-e43a-4002-9cc5-2d25a8a7e04e/storehouse.jpgvanda-production-assets.s3.amazonaw... https://vanda-production-assets.s3.amazonaws.com/2026/04/20/08/26/57/0382b05a-e43a-4002-9cc5-2d25a8a7e04e/storehouse.jpg — 200 — 90.2 KiB — 242 ms — http/1.1https://assets-cdn.vam.ac.uk/2025/10/29/13/29/53/18d90b98-7ea3-4394-b233-75cccbbf525e/640.jpgassets-cdn.vam.ac.uk/2025/10/29/13/... https://assets-cdn.vam.ac.uk/2025/10/29/13/29/53/18d90b98-7ea3-4394-b233-75cccbbf525e/640.jpg — 200 — 50.1 KiB — 48 ms — h2https://assets-cdn.vam.ac.uk/2026/02/19/15/08/27/7d0869b3-f0b9-402b-b218-9a3eac13f9cc/640.jpgassets-cdn.vam.ac.uk/2026/02/19/15/... https://assets-cdn.vam.ac.uk/2026/02/19/15/08/27/7d0869b3-f0b9-402b-b218-9a3eac13f9cc/640.jpg — 200 — 20.4 KiB — 51 ms — h2https://assets-cdn.vam.ac.uk/2025/07/03/11/54/11/bd1c8b61-bcc0-4149-a56c-dabb05ed18be/640.jpgassets-cdn.vam.ac.uk/2025/07/03/11/... https://assets-cdn.vam.ac.uk/2025/07/03/11/54/11/bd1c8b61-bcc0-4149-a56c-dabb05ed18be/640.jpg — 200 — 58.6 KiB — 31 ms — h2https://assets-cdn.vam.ac.uk/2026/04/13/17/46/24/351bb54d-0d0a-4b9f-b3fc-9fcb567e6c16/640.jpgassets-cdn.vam.ac.uk/2026/04/13/17/... https://assets-cdn.vam.ac.uk/2026/04/13/17/46/24/351bb54d-0d0a-4b9f-b3fc-9fcb567e6c16/640.jpg — 200 — 16.6 KiB — 32 ms — h2https://assets-cdn.vam.ac.uk/2025/05/13/14/58/03/0eb76032-abf2-4ca6-b1b0-591b274068b0/640.jpgassets-cdn.vam.ac.uk/2025/05/13/14/... https://assets-cdn.vam.ac.uk/2025/05/13/14/58/03/0eb76032-abf2-4ca6-b1b0-591b274068b0/640.jpg — 200 — 47.7 KiB — 34 ms — h2https://assets-cdn.vam.ac.uk/2025/09/08/11/01/42/1494759e-03a7-4d2d-90e0-2ab21db16db9/640.jpgassets-cdn.vam.ac.uk/2025/09/08/11/... https://assets-cdn.vam.ac.uk/2025/09/08/11/01/42/1494759e-03a7-4d2d-90e0-2ab21db16db9/640.jpg — 200 — 101.3 KiB — 46 ms — h2https://www.vam.ac.uk/fonts/Spiller-Upright-weight-VF-Web-V2.woff2www.vam.ac.uk/fonts/Spiller-Upright... https://www.vam.ac.uk/fonts/Spiller-Upright-weight-VF-Web-V2.woff2 — 200 — 79.1 KiB — 19 ms — h2https://www.vam.ac.uk/fonts/SpillerWidth-Upright-width_weight-VF-Web.woff2www.vam.ac.uk/fonts/SpillerWidth-Up... https://www.vam.ac.uk/fonts/SpillerWidth-Upright-width_weight-VF-Web.woff2 — 200 — 98.6 KiB — 29 ms — h2https://www.vam.ac.uk/services/search/suggest/promotedwww.vam.ac.uk/services/search/sugge... https://www.vam.ac.uk/services/search/suggest/promoted — 200 — 22.0 KiB — 15 ms — h2
0 ms 500 ms 1.0 s 1.5 s FCP 876 ms LCP 1.5 shttps://vam.ac.uk// https://vam.ac.uk/ — 301 — 175 B — 111 ms — http/1.1https://www.vam.ac.uk/www.vam.ac.uk/ https://www.vam.ac.uk/ — 200 — 21.6 KiB — 10 ms — h2https://www.vam.ac.uk/assets/application-c50bba875c3aa362ba61ad6702a6df308dfb3678ca885c649138569e328f1608.csswww.vam.ac.uk/assets/application-c5... https://www.vam.ac.uk/assets/application-c50bba875c3aa362ba61ad6702a6df308dfb3678ca885c649138569e328f1608.css — 200 — 44.0 KiB — 7 ms — h2https://cdn.cookielaw.org/scripttemplates/otSDKStub.jscdn.cookielaw.org/scripttemplates/o... https://cdn.cookielaw.org/scripttemplates/otSDKStub.js — 200 — 9.1 KiB — 100 ms — h2https://assets-cdn.vam.ac.uk/2026/04/14/11/22/04/4e5b727e-79a1-419d-8d00-8928b90a0409/1920.jpgassets-cdn.vam.ac.uk/2026/04/14/11/... https://assets-cdn.vam.ac.uk/2026/04/14/11/22/04/4e5b727e-79a1-419d-8d00-8928b90a0409/1920.jpg — 200 — 174.1 KiB — 16 ms — h2https://www.vam.ac.uk/assets/favicon/manifest-3c37297d439cc0a5dc5f02e7b9bd80598c41b60a2346b24f0618ef8eaa72258b.jsonwww.vam.ac.uk/assets/favicon/manife... https://www.vam.ac.uk/assets/favicon/manifest-3c37297d439cc0a5dc5f02e7b9bd80598c41b60a2346b24f0618ef8eaa72258b.json — 200 — 799 B — 7 ms — h2https://www.vam.ac.uk/packs/js/vam-fractal-cdd985373148c42cc3d6.jswww.vam.ac.uk/packs/js/vam-fractal-... https://www.vam.ac.uk/packs/js/vam-fractal-cdd985373148c42cc3d6.js — 200 — 10.6 KiB — 4 ms — h2https://www.vam.ac.uk/packs/js/application-9b0a6e0d56041a444b5e.jswww.vam.ac.uk/packs/js/application-... https://www.vam.ac.uk/packs/js/application-9b0a6e0d56041a444b5e.js — 200 — 9.6 KiB — 3 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-P24KW5www.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-P24KW5 — 200 — 198.3 KiB — 148 ms — h2https://cdn.cookielaw.org/consent/063ed2c5-fa48-4395-bdb3-999b05bd01fd/063ed2c5-fa48-4395-bdb3-999b05bd01fd.jsoncdn.cookielaw.org/consent/063ed2c5-... https://cdn.cookielaw.org/consent/063ed2c5-fa48-4395-bdb3-999b05bd01fd/063ed2c5-fa48-4395-bdb3-999b05bd01fd.json — 200 — 2.4 KiB — 72 ms — h2https://www.vam.ac.uk/assets/vam-sprite-336679439415943192abd08310316502cdd2edb65ff20acfeb4bd8ed7ce9287d.svgwww.vam.ac.uk/assets/vam-sprite-336... https://www.vam.ac.uk/assets/vam-sprite-336679439415943192abd08310316502cdd2edb65ff20acfeb4bd8ed7ce9287d.svg — 200 — 57.9 KiB — 5 ms — h2data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp… — 200 — 0 B — 0 ms — datadata:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C… — 200 — 0 B — 0 ms — datadata:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16' %3E%3C… — 200 — 0 B — 0 ms — datadata:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp…www.w3.org/2000/svg' fill='none' vi... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 16 16'%3E%3Cp… — 200 — 0 B — 0 ms — datahttps://assets-cdn.vam.ac.uk/2022/07/18/10/43/04/1d1d02e9-ef6f-4ada-bc85-cc092f656808/640.jpgassets-cdn.vam.ac.uk/2022/07/18/10/... https://assets-cdn.vam.ac.uk/2022/07/18/10/43/04/1d1d02e9-ef6f-4ada-bc85-cc092f656808/640.jpg — 200 — 67.9 KiB — 40 ms — h2https://assets-cdn.vam.ac.uk/2026/04/18/06/34/11/01b8ec10-7eef-497e-b704-a4abfa2ff2ec/320.jpgassets-cdn.vam.ac.uk/2026/04/18/06/... https://assets-cdn.vam.ac.uk/2026/04/18/06/34/11/01b8ec10-7eef-497e-b704-a4abfa2ff2ec/320.jpg — 200 — 35.3 KiB — 47 ms — h2https://assets-cdn.vam.ac.uk/2025/11/20/15/22/58/77c37dbf-e883-4c09-92ed-cf7474716c16/320.jpgassets-cdn.vam.ac.uk/2025/11/20/15/... https://assets-cdn.vam.ac.uk/2025/11/20/15/22/58/77c37dbf-e883-4c09-92ed-cf7474716c16/320.jpg — 200 — 45.4 KiB — 45 ms — h2https://assets-cdn.vam.ac.uk/2022/07/18/10/51/13/e7d3df02-176f-4398-bb56-f47943a77124/320.jpgassets-cdn.vam.ac.uk/2022/07/18/10/... https://assets-cdn.vam.ac.uk/2022/07/18/10/51/13/e7d3df02-176f-4398-bb56-f47943a77124/320.jpg — 200 — 50.2 KiB — 31 ms — h2https://assets-cdn.vam.ac.uk/2024/11/19/13/03/14/dc9ed5b0-0865-434f-9993-90b9cbe21a74/640.jpgassets-cdn.vam.ac.uk/2024/11/19/13/... https://assets-cdn.vam.ac.uk/2024/11/19/13/03/14/dc9ed5b0-0865-434f-9993-90b9cbe21a74/640.jpg — 200 — 48.8 KiB — 49 ms — h2https://vanda-production-assets.s3.amazonaws.com/2026/04/20/08/26/57/0382b05a-e43a-4002-9cc5-2d25a8a7e04e/storehouse.jpgvanda-production-assets.s3.amazonaw... https://vanda-production-assets.s3.amazonaws.com/2026/04/20/08/26/57/0382b05a-e43a-4002-9cc5-2d25a8a7e04e/storehouse.jpg — 200 — 90.2 KiB — 242 ms — http/1.1https://assets-cdn.vam.ac.uk/2025/10/29/13/29/53/18d90b98-7ea3-4394-b233-75cccbbf525e/640.jpgassets-cdn.vam.ac.uk/2025/10/29/13/... https://assets-cdn.vam.ac.uk/2025/10/29/13/29/53/18d90b98-7ea3-4394-b233-75cccbbf525e/640.jpg — 200 — 50.1 KiB — 48 ms — h2https://assets-cdn.vam.ac.uk/2026/02/19/15/08/27/7d0869b3-f0b9-402b-b218-9a3eac13f9cc/640.jpgassets-cdn.vam.ac.uk/2026/02/19/15/... https://assets-cdn.vam.ac.uk/2026/02/19/15/08/27/7d0869b3-f0b9-402b-b218-9a3eac13f9cc/640.jpg — 200 — 20.4 KiB — 51 ms — h2https://assets-cdn.vam.ac.uk/2025/07/03/11/54/11/bd1c8b61-bcc0-4149-a56c-dabb05ed18be/640.jpgassets-cdn.vam.ac.uk/2025/07/03/11/... https://assets-cdn.vam.ac.uk/2025/07/03/11/54/11/bd1c8b61-bcc0-4149-a56c-dabb05ed18be/640.jpg — 200 — 58.6 KiB — 31 ms — h2https://assets-cdn.vam.ac.uk/2026/04/13/17/46/24/351bb54d-0d0a-4b9f-b3fc-9fcb567e6c16/640.jpgassets-cdn.vam.ac.uk/2026/04/13/17/... https://assets-cdn.vam.ac.uk/2026/04/13/17/46/24/351bb54d-0d0a-4b9f-b3fc-9fcb567e6c16/640.jpg — 200 — 16.6 KiB — 32 ms — h2https://assets-cdn.vam.ac.uk/2025/05/13/14/58/03/0eb76032-abf2-4ca6-b1b0-591b274068b0/640.jpgassets-cdn.vam.ac.uk/2025/05/13/14/... https://assets-cdn.vam.ac.uk/2025/05/13/14/58/03/0eb76032-abf2-4ca6-b1b0-591b274068b0/640.jpg — 200 — 47.7 KiB — 34 ms — h2https://assets-cdn.vam.ac.uk/2025/09/08/11/01/42/1494759e-03a7-4d2d-90e0-2ab21db16db9/640.jpgassets-cdn.vam.ac.uk/2025/09/08/11/... https://assets-cdn.vam.ac.uk/2025/09/08/11/01/42/1494759e-03a7-4d2d-90e0-2ab21db16db9/640.jpg — 200 — 101.3 KiB — 46 ms — h2https://www.vam.ac.uk/fonts/Spiller-Upright-weight-VF-Web-V2.woff2www.vam.ac.uk/fonts/Spiller-Upright... https://www.vam.ac.uk/fonts/Spiller-Upright-weight-VF-Web-V2.woff2 — 200 — 79.1 KiB — 19 ms — h2https://www.vam.ac.uk/fonts/SpillerWidth-Upright-width_weight-VF-Web.woff2www.vam.ac.uk/fonts/SpillerWidth-Up... https://www.vam.ac.uk/fonts/SpillerWidth-Upright-width_weight-VF-Web.woff2 — 200 — 98.6 KiB — 29 ms — h2https://www.vam.ac.uk/services/search/suggest/promotedwww.vam.ac.uk/services/search/sugge... https://www.vam.ac.uk/services/search/suggest/promoted — 200 — 22.0 KiB — 15 ms — h2data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100' fill='currentCol…www.w3.org/2000/svg' viewBox='0 0 1... data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100' fill='currentCol… — 200 — 0 B — 0 ms — datahttps://geolocation.onetrust.com/cookieconsentpub/v1/geo/locationgeolocation.onetrust.com/cookiecons... https://geolocation.onetrust.com/cookieconsentpub/v1/geo/location — 200 — 308 B — 44 ms — h2https://cdn.cookielaw.org/scripttemplates/202510.1.0/otBannerSdk.jscdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202510.1.0/otBannerSdk.js — 200 — 123.4 KiB — 51 ms — h2https://www.vam.ac.uk/assets/favicon/favicon-5dd27650aed8a5287300ee5031cd889624ce2514ead48f3ff9709f7f2b22cc5b.icowww.vam.ac.uk/assets/favicon/favico... https://www.vam.ac.uk/assets/favicon/favicon-5dd27650aed8a5287300ee5031cd889624ce2514ead48f3ff9709f7f2b22cc5b.ico — 200 — 11.1 KiB — 3 ms — h2https://cdn.cookielaw.org/consent/063ed2c5-fa48-4395-bdb3-999b05bd01fd/0198c743-ea34-72da-8fe3-61eaa435a59b/en-us.jsoncdn.cookielaw.org/consent/063ed2c5-... https://cdn.cookielaw.org/consent/063ed2c5-fa48-4395-bdb3-999b05bd01fd/0198c743-ea34-72da-8fe3-61eaa435a59b/en-us.json — 200 — 39.0 KiB — 57 ms — h2https://cdn.cookielaw.org/vendorlist/iab2V2Data.jsoncdn.cookielaw.org/vendorlist/iab2V2... https://cdn.cookielaw.org/vendorlist/iab2V2Data.json — 200 — 86.9 KiB — 55 ms — h2https://cdn.cookielaw.org/scripttemplates/202510.1.0/otTCF.jscdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202510.1.0/otTCF.js — 200 — 17.7 KiB — 29 ms — h2https://cdn.cookielaw.org/scripttemplates/202510.1.0/assets/otCenterRounded.jsoncdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202510.1.0/assets/otCenterRounded.json — 200 — 2.9 KiB — 28 ms — h2https://cdn.cookielaw.org/scripttemplates/202510.1.0/assets/v2/otPcCenter.jsoncdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202510.1.0/assets/v2/otPcCenter.json — 200 — 13.3 KiB — 31 ms — h2https://cdn.cookielaw.org/scripttemplates/202510.1.0/assets/otCommonStyles.csscdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202510.1.0/assets/otCommonStyles.css — 200 — 4.6 KiB — 30 ms — h2https://cdn.cookielaw.org/logos/static/ot_guard_logo.svgcdn.cookielaw.org/logos/static/ot_g... https://cdn.cookielaw.org/logos/static/ot_guard_logo.svg — 200 — 556 B — 29 ms — h2https://cdn.cookielaw.org/logos/bbace08b-a77c-4d23-a1ee-1d0cd203c6ab/12912d69-0345-47a4-8865-db37d2e9d352/c9851145-71a5-48fa-8ccb-1a0e818f384f/va-master-logo.pngcdn.cookielaw.org/logos/bbace08b-a7... https://cdn.cookielaw.org/logos/bbace08b-a77c-4d23-a1ee-1d0cd203c6ab/12912d69-0345-47a4-8865-db37d2e9d352/c9851145-71a5-48fa-8ccb-1a0e818f384f/va-master-logo.png — 200 — 2.1 KiB — 30 ms — h2https://cdn.cookielaw.org/logos/static/powered_by_logo.svgcdn.cookielaw.org/logos/static/powe... https://cdn.cookielaw.org/logos/static/powered_by_logo.svg — 200 — 2.6 KiB — 29 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 486ms · 352KB · £3/mo
Unattributable
Other
Optional
Execution 181ms
Transfer 0 KB
Monthly Cost £1/mo
www.vam.ac.uk
Other
Optional
Execution 120ms
Transfer 22 KB
Monthly Cost £1/mo
OneTrust
Consent
Essential
Execution 69ms
Transfer 123 KB
Unused 48%
Monthly Cost £0/mo
OneTrust
Consent
Essential
Execution 65ms
Transfer 9 KB
Monthly Cost £0/mo
Google Tag Manager
Tag Manager
Optional
Execution 51ms
Transfer 198 KB
Unused 40%
Monthly Cost £0/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