www.w3.org speed test — 20 Oct 2026

Measured from the wfix.shop server on 20 October 2026 at 12:35 UTC. Grade A (92/100), with the screenshots, the timings and the fixes that matter.

https://www.w3.org/

20 October 2026 at 12:35 UTC · Free test · report pt_c5420194dc9f
Grade
A
92/100
Performance100/100
Structure79/100

12 audit(s) passed, 4 need work

First byte (TTFB)166 msmeasured from this server
Fully loaded1.09 sfirst byte + slowest asset
Requests21document + assets
Page weight840.6 KBcompressed transfer
HTML document8.8 KBbr
ProtocolHTTP/3cloudflare

Where the first byte went

  • DNS lookup 50 ms 30%
  • TCP connect 20 ms 12%
  • Server wait 95 ms 57%

Measured on the connection that fetched the HTML. Every other request on the page waits for the end of this bar before it can start.

How this page compares

First bytefaster than 97% of 4,999 pages tested here166 ms against a median of 449 ms
Page weightheavier than 58% of 4,999 pages tested here840.6 KB against a median of 650.3 KB
Fully loadedfaster than 90% of 4,999 pages tested here1.09 s against a median of 1.84 s
Requestssends fewer requests than 78% of 4,999 pages tested here21 against a median of 26

Every report published here is in this comparison, so it is a reference population of pages tested from one server - not a benchmark of the whole web.

What these numbers mean

  • The server answered in 166 ms, which is fast: almost all of the wait is the page itself, not the host.
  • The page transfers 840.6 KB over 21 request(s). Images files are 92% of it, so resize and recompress the largest images before anything else.
  • The HTML itself arrives br-compressed.
  • It runs over HTTP/3, so the assets share a connection instead of opening one each.
  • The largest element painted at 352 ms, inside the 2.5 s Google calls good.
  • Layout stayed still (CLS 0.001), so nothing jumps under the reader's cursor.
  • The main thread was blocked for 9 ms in total, which is not enough to feel.

Fix first: Image delivery and format - Serve WebP or AVIF with a JPEG fallback, size images to the space they occupy, and lazy-load anything below the fold. Images are usually more than half of a slow page.

Read on one shared server, not a visitor's phone: use it to compare pages against each other, not as a promise about every connection. We fix what these tests find.

Screenshot

What the page looks like

Loaded in headless Chromium on this server. Click an image to open it full size.

Desktop screenshot of www.w3.org
Desktop 1366 × 768 · 135.6 KB · page is 3648 px tall
Mobile screenshot of www.w3.org
Mobile 390 × 844 · 76.1 KB · page is 6000 px tall

Browser render

The same URL loaded in a real browser, so these are the readings curl cannot produce. The grade above is still built from the server measurements.

Largest contentful paint352 msgood is under 2.5 s
Cumulative layout shift0.001under 0.1 is stable
Total blocking time9 mslong tasks during load
First contentful paint352 msfirst content on screen
Browser page weight541.6 KB26 request(s), scripts included
Largest contentful paint352 ms
Goodgood under 2.5 s, poor over 4 s
Cumulative layout shift0.001
Goodgood under 0.1, poor over 0.25
Total blocking time9 ms
Goodgood under 200 ms, poor over 600 ms

Page weight by type

What the page is made of

Images 14 requests
776.8 KB 92%
Css 3 requests
52.1 KB 6%
Javascript 1 request
2.9 KB 0%

Transfer size, compressed as sent. 21 request(s) in total, 840.6 KB across all of them.

Top issues

Image delivery and format

high impact

2 image(s) over 200 KB and 2 large image(s) still served as JPEG or PNG.

Fix: Serve WebP or AVIF with a JPEG fallback, size images to the space they occupy, and lazy-load anything below the fold. Images are usually more than half of a slow page.

Render-blocking resources

high impact

4 render-blocking resource(s) in the document head (1 script(s), 3 stylesheet(s)). The page cannot paint until each one arrives.

Fix: Add defer or async to scripts that do not change the first paint, inline the critical CSS, and load the rest with media="print" plus an onload swap.

Cache static assets

medium impact

11 asset(s) answer without a Cache-Control max-age, so browsers revalidate them on every visit.

Fix: Version filenames on change and serve them with a long max-age plus immutable. That is what makes a returning visitor fast.

Avoid extra redirects

medium impact

1 redirect hop(s) before the page load started, each one a full round trip before the first byte.

Fix: Link to the canonical URL (and make sure http, the apex domain and www all point at it) so no visitor pays a redirect first.

Waterfall

Slowest requests

IMAGESwww.w3.org/cms-uploads/_360xAUTO_crop_center-cent…
926 ms
OTHERwww.w3.org/cms-uploads/blog/2026-10_EPUB-34/_360x…
921 ms
OTHERwww.w3.org/cms-uploads/blog/2026-10_EPUB-34/_920x…
903 ms
IMAGESwww.w3.org/cms-uploads/_360xAUTO_crop_center-cent…
877 ms
IMAGESwww.w3.org/cms-uploads/_360xAUTO_crop_center-cent…
872 ms
IMAGESwww.w3.org/cms-uploads/Hero-illustrations/groups-…
872 ms
JAVASCRIPTwww.w3.org/assets/website-2021/js/libraries/fontf…
860 ms
IMAGESwww.w3.org/assets/logos/w3c-2025/svg/w3c.svg
850 ms
IMAGESwww.w3.org/cms-uploads/marvin-meyer-SYTO3xs06fU-u…
839 ms
IMAGESwww.w3.org/cms-uploads/ryan-quintal-US9Tc9pKNBU-u…
838 ms

Each bar is one request's own response time, scaled to the slowest. Assets were fetched in parallel, so the bars overlap in real time rather than stacking. first party third party

RequestTypeStatusTimeSize
https://www.w3.org/cms-uploads/_360xAUTO_crop_center-center_none/marvin-meyer-SYTO3xs06fU-unsplash.jpgimages200926 ms20.9 KB
https://www.w3.org/cms-uploads/blog/2026-10_EPUB-34/_360xAUTO_crop_center-center_none/epub34_roll_layout_demo.pngother403921 ms0 B
https://www.w3.org/cms-uploads/blog/2026-10_EPUB-34/_920xAUTO_crop_center-center_none/epub34_roll_layout_demo.pngother403903 ms0 B
https://www.w3.org/cms-uploads/_360xAUTO_crop_center-center_none/ryan-quintal-US9Tc9pKNBU-unsplash.jpgimages200877 ms25.9 KB
https://www.w3.org/cms-uploads/_360xAUTO_crop_center-center_none/banner1.jpgimages200872 ms21.6 KB
https://www.w3.org/cms-uploads/Hero-illustrations/groups-2025.svgimages200872 ms17.9 KB
https://www.w3.org/assets/website-2021/js/libraries/fontfaceobserver.js?ver=1.6javascript200860 ms2.9 KB
https://www.w3.org/assets/logos/w3c-2025/svg/w3c.svgimages200850 ms30.5 KB
https://www.w3.org/cms-uploads/marvin-meyer-SYTO3xs06fU-unsplash.jpgimages200839 ms285.8 KB
https://www.w3.org/cms-uploads/ryan-quintal-US9Tc9pKNBU-unsplash.jpgimages200838 ms272.6 KB
https://www.w3.org/cms-uploads/banner1.jpgimages200838 ms91.7 KB
https://www.w3.org/assets/logos/w3c-2025/favicons/favicon-32.pngimages200827 ms1.3 KB
https://www.w3.org/assets/website-2021/svg/github.svgimages200815 ms1.0 KB
https://www.w3.org/assets/website-2021/svg/avatar.svgimages200790 ms401 B
https://www.w3.org/assets/website-2021/svg/search.svgimages200787 ms366 B
https://www.w3.org/assets/website-2021/styles/print.css?ver=1.6css200783 ms5.5 KB
https://www.w3.org/assets/website-2021/svg/mastodon.svgimages200770 ms594 B
https://www.w3.org/assets/website-2021/styles/core.css?ver=1.6css200762 ms37.3 KB
https://www.w3.org/assets/website-2021/styles/advanced.css?ver=1.6css200762 ms9.3 KB
https://www.w3.org/assets/logos/w3c-2025/favicons/favicon-180.pngimages200762 ms6.3 KB
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