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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
70
GRADE
C
FIX
3
REVIEW
4
PASS
5
INFO
2

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

Mobile Desktop
74
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.
96
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.

847 ms

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

3.05 s

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

35 ms

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

0.029

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

3.56 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.

4.62 s

Page Load Progression

427 ms
854 ms
1.3 s
1.7 s
2.1 s
2.6 s
3.0 s
3.4 s
Checks
14
5 PASS 4 REVIEW 3 FIX
F
Page Weight Budget
Action
7.7 MB transferred, 178 requests
FIX
7.7 MB transferred, 178 requests
Critical::
Page weighs 12.6 MB (7.7 MB transferred)
Warning::
Images are 5.5 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 5.5 MB
Warning::
JavaScript is 1.6 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.6 MB
Info::
Fonts are 437 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 437 KB
Warning::
178 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.6 g CO2 per page load
7.7 MB / 2.4 MB budget
7.7 MB transferred
178 requests
1.6 g CO2 per page load
Images 5.5 MiB 71%
JavaScript 1.6 MiB 20%
Fonts 436.9 KiB 6%
HTML 138.1 KiB 2%
CSS 54.1 KiB 1%
Other 30.0 KiB 0%
Other 13.4 KiB 0%
Other 3.8 KiB 0%
Other 683 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

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.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

D
Third-Party Impact
Action
77% third-party, 0 ms blocking
FIX
77% third-party, 0 ms blocking
Warning::
Third-party code accounts for 77% of page weight (6.0 MiB of 7.7 MiB)
Info::
Third-party blocking time is low (0 ms)
23%
77%
First-party Third-party
F
JS Bundles
Action
22 scripts, 936 KB unused
FIX
22 scripts, 936 KB unused
Warning::
https://www.formula1.com/assets/home/_next/static/...: 343 KB unused (80%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.formula1.com/assets/home/_next/static/...: 140 KB unused (83%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://securepubads.g.doubleclick.net/pagead/mana...: 139 KB unused (76%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-K8R...: 82 KB unused (50%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://consent.formula1.com/Notice.8f529.js: 62 KB unused (69%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 936 KB
936 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.formula1.com/assets/home/_next/static/chunks/785-aa4f3c926a14e678.js433 KB343 KB (80%)✓1st
https://www.formula1.com/assets/home/_next/static/chunks/b44ffc44-5babc187430cb039.js170 KB140 KB (83%)✓1st
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604020101/pubads_impl.js183 KB139 KB (76%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-K8R56M6&l=dataLayer164 KB82 KB (50%)✓3rd
https://consent.formula1.com/Notice.8f529.js91 KB62 KB (69%)✓3rd
https://www.formula1.com/assets/home/_next/static/chunks/6bdcba90-4f94600a7a96a195.js76 KB61 KB (82%)✓1st
https://www.formula1.com/assets/home/_next/static/chunks/74-1b0ad625aae7b57b.js87 KB55 KB (63%)✓1st
https://www.googletagmanager.com/gtm.js?id=GTM-NTR4PPW163 KB53 KB (33%)✓3rd
https://code.jquery.com/jquery-3.7.1.slim.min.js24 KB—✓3rd
https://www.googletagservices.com/tag/js/gpt.js34 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

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

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
Image Optimization
Action
121 images, 0 KB saveable
REVIEW
121 images, 0 KB saveable
Warning::
https://www.formula1.com/assets/home/_next/static/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.formula1.com/assets/home/_next/static/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.formula1.com/assets/home/_next/static/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
121 images 5.5 MB
0 oversized -0 KB
17 legacy format
3 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

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

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

C
JS Execution Cost
Action
1582ms total JS execution
REVIEW
1582ms total JS execution
Warning::
https://www.formula1.com/: 617ms CPU time
Warning::
Unattributable: 319ms CPU time
Info::
https://www.formula1.com/assets/home/_next/static/...: 160ms CPU time
Info::
https://www.formula1.com/assets/home/_next/static/...: 121ms CPU time
Info::
https://www.formula1.com/assets/home/_next/static/...: 96ms CPU time
Info::
Third-party scripts: 531ms (34% of total)

Main Thread Breakdown

Script Evaluation 29% Other 25% Style & Layout 24% Script Parsing & Compilation 10% Rendering 7%
ScriptTotalScriptingParse/CompileParty
https://www.formula1.com/617ms4ms28ms1st
Unattributable319ms3ms0ms3rd
https://www.formula1.com/assets/home/_next/static/chunks/528-bc7c2743f4f9dae5.js160ms136ms3ms1st
https://www.formula1.com/assets/home/_next/static/chunks/785-aa4f3c926a14e678.js121ms81ms40ms1st
https://www.formula1.com/assets/home/_next/static/chunks/74-1b0ad625aae7b57b.js96ms3ms10ms1st
https://consent.formula1.com/Notice.8f529.js75ms60ms7ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-NTR4PPW72ms55ms13ms3rd
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604020101/pubads_impl.js65ms35ms20ms3rd
https://www.formula1.com/assets/home/_next/static/chunks/1dd3208c-b647b486c64d44a6.js56ms42ms5ms1st
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

B
HTTP Caching
max-age=0, s-maxage=60, stale-while-revalidate=300, stale-if-error=86400
REVIEW
max-age=0, s-maxage=60, stale-while-revalidate=300, stale-if-error=86400
Info::
Cache-Control header is set
Got: max-age=0, s-maxage=60, stale-while-revalidate=300, stale-if-error=86400
Info::
CDN TTL: 1 minute (s-maxage=60)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

max-age=0, s-maxage=60, stale-while-revalidate=300, stale-if-error=86400

DirectiveValueMeaning
max-age0Cache for 0 seconds
s-maxage60CDN caches for 1 minute
stale-while-revalidate300Serve stale for 5 minutes while fetching fresh
stale-if-error86400
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+
Font Loading
14 fonts (437 KB)
PASS
14 fonts (437 KB)
Info::
14 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

14

437 KB total

Render-blocking

0

of 14

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s FCP 847 ms LCP 3.1 shttps://www.formula1.com/s/fonts/titillium/TitilliumWeb-Regular.ttfTitilliumWeb-Regular.ttf https://www.formula1.com/s/fonts/titillium/TitilliumWeb-Regular.ttf — 56.6 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/titillium/TitilliumWeb-Bold.ttfTitilliumWeb-Bold.ttf https://www.formula1.com/s/fonts/titillium/TitilliumWeb-Bold.ttf — 53.2 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/formula1/Formula1-Regular.woff2Formula1-Regular.woff2 https://www.formula1.com/s/fonts/formula1/Formula1-Regular.woff2 — 25.0 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/formula1/Formula1-Bold.woff2Formula1-Bold.woff2 https://www.formula1.com/s/fonts/formula1/Formula1-Bold.woff2 — 25.3 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/formula1/Formula1-Black.woff2Formula1-Black.woff2 https://www.formula1.com/s/fonts/formula1/Formula1-Black.woff2 — 26.8 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/titillium/TitilliumWeb-SemiBold.ttfTitilliumWeb-SemiBold.ttf https://www.formula1.com/s/fonts/titillium/TitilliumWeb-SemiBold.ttf — 55.9 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/kh-interference-f1/KHInterferenceF1-Bold.woff2KHInterferenceF1-Bold.w... https://www.formula1.com/s/fonts/kh-interference-f1/KHInterferenceF1-Bold.woff2 — 21.0 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/apax-th/Apax-TAG-Heuer-Regular.woff2Apax-TAG-Heuer-Regular.... https://www.formula1.com/s/fonts/apax-th/Apax-TAG-Heuer-Regular.woff2 — 34.4 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/kh-interference-f1/KHInterferenceF1-Regular.woff2KHInterferenceF1-Regula... https://www.formula1.com/s/fonts/kh-interference-f1/KHInterferenceF1-Regular.woff2 — 20.0 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/apax-th/Apax-TAG-Heuer-Superbold.woff2Apax-TAG-Heuer-Superbol... https://www.formula1.com/s/fonts/apax-th/Apax-TAG-Heuer-Superbold.woff2 — 35.2 KiB — 0 ms — font-display: swaphttps://www.formula1.com/s/fonts/apax-th/Apax-TAG-Heuer-Medium.woff2Apax-TAG-Heuer-Medium.w... https://www.formula1.com/s/fonts/apax-th/Apax-TAG-Heuer-Medium.woff2 — 34.8 KiB — 0 ms — font-display: swaphttps://www.formula1.com/etc/designs/fom-website/fonts/F1Regular/Formula1-Regular.woff2Formula1-Regular.woff2 https://www.formula1.com/etc/designs/fom-website/fonts/F1Regular/Formula1-Regular.woff2 — 25.1 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/titilliumweb/v19/NaPecZTIAOhVxoMyOr9n_E7fdMPmDaZRbrw.woff2NaPecZTIAOhVxoMyOr9n_E7... https://fonts.gstatic.com/s/titilliumweb/v19/NaPecZTIAOhVxoMyOr9n_E7fdMPmDaZRbrw.woff2 — 12.1 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/titilliumweb/v19/NaPDcZTIAOhVxoMyOr9n_E7ffHjDGItzY5abuWI.woff2NaPDcZTIAOhVxoMyOr9n_E7... https://fonts.gstatic.com/s/titilliumweb/v19/NaPDcZTIAOhVxoMyOr9n_E7ffHjDGItzY5abuWI.woff2 — 11.5 KiB — 0 ms — font-display: swap
TitilliumWeb-Regular.ttf ttf swap
Size 57 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
TitilliumWeb-Bold.ttf ttf swap
Size 53 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Formula1-Regular.woff2 woff2 swap
Size 25 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Formula1-Bold.woff2 woff2 swap
Size 25 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Formula1-Black.woff2 woff2 swap
Size 27 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
TitilliumWeb-SemiBold.ttf ttf swap
Size 56 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
KHInterferenceF1-Bold.w... woff2 swap
Size 21 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Apax-TAG-Heuer-Regular.... woff2 swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KHInterferenceF1-Regula... woff2 swap
Size 20 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Apax-TAG-Heuer-Superbol... woff2 swap
Size 35 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Apax-TAG-Heuer-Medium.w... woff2 swap
Size 35 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Formula1-Regular.woff2 woff2 swap
Size 25 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
NaPecZTIAOhVxoMyOr9n_E7... woff2 swap
Size 12 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
NaPDcZTIAOhVxoMyOr9n_E7... woff2 swap
Size 11 KB
Load time 0 ms
Start 0 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)

Fixing the unchecked items could save ~50 KB and ~100 ms

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
178 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
34% of JavaScript execution is third-party
First-party Third-party 531ms · 437KB · $7/mo
Unattributable
Other
Costly
Execution 319ms
Transfer 0 KB
Monthly Cost $4/mo
consent.formula1.com
Other
Optional
Execution 75ms
Transfer 91 KB
Unused 69%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 72ms
Transfer 163 KB
Unused 33%
Monthly Cost $1/mo
securepubads.g.doubleclick.net
Other
Optional
Execution 65ms
Transfer 183 KB
Unused 76%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 319ms and costs ~$4/month

Unattributable takes 319ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

69% of consent.formula1.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

76% of securepubads.g.doubleclick.net's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

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.

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