worldwideweb.cern.ch
Data from Aug 21, 2026, 9:35 AM UTC — 9h old.
Built Awesome · 1 measurement · since Aug 21, 2026 · last attempt 9h
Core Web Vitals field data, url-level
Real Chrome users, 28-day window (2026-07-23 → 2026-08-19). This is what Google measures you on.
Scores
Lab metrics Lighthouse, mobile
| Metric | Current | Previous | Change | Best | Worst | Trend |
|---|---|---|---|---|---|---|
| LCP Largest Contentful Paint | 982 ms | — | — | 982 ms | 982 ms | |
| CLS Cumulative Layout Shift | 0 | — | — | 0 | 0 | |
| TBT Total Blocking Time | 102 ms | — | — | 102 ms | 102 ms | |
| FCP First Contentful Paint | 907 ms | — | — | 907 ms | 907 ms | |
| Speed Index | 1.72 s | — | — | 1.72 s | 1.72 s | |
| TTFB Time to First Byte | 674 ms | — | — | 674 ms | 674 ms |
What LCP is made of
A flat LCP number tells you something regressed. The subparts tell you whether it was the server, resource discovery, the download, or rendering.
Field data Chrome UX Report, url-level
Real Chrome users, 28-day trailing window (2026-07-23 → 2026-08-19). This is what Google measures you on.
| Metric | p75 | Rating | Distribution (good / needs work / poor) |
|---|---|---|---|
| LCP CWV | 1.58 s | good | 88.1% good |
| INP CWV Interaction to Next Paint — field only, Lighthouse cannot measure this in a lab run | 102 ms | good | 92.1% good |
| CLS CWV | 0.060 | good | 76.3% good |
| FCP | 1.59 s | good | 79.2% good |
| TTFB | 854 ms | needs-improvement | 73% good |
Lab vs field
Lab LCP 982 ms · field p75 1.58 s · real users are 1.61× slower than the lab. A gap this wide usually means real users are on slower devices or networks than the simulated ones — the lab number is flattering you.
Field history 25 weeks
Weekly p75 from the CrUX History API, backfilled in a single request.
| Week ending | LCP | INP | CLS | FCP | TTFB |
|---|---|---|---|---|---|
| 2026-08-15 | 1.48 s | 95 ms | 0.160 | 1.48 s | 763 ms |
| 2026-08-08 | 1.39 s | 93 ms | 0.170 | 1.39 s | 752 ms |
| 2026-08-01 | 1.36 s | 90 ms | 0.160 | 1.36 s | 734 ms |
| 2026-07-25 | 1.35 s | 90 ms | 0.160 | 1.36 s | 738 ms |
| 2026-07-18 | 1.37 s | 86 ms | 0.160 | 1.36 s | 770 ms |
| 2026-07-11 | 1.51 s | — | 0.030 | 1.53 s | 970 ms |
| 2026-07-04 | — | — | — | — | — |
| 2026-06-27 | 1.61 s | 87 ms | 0 | 1.61 s | 1.16 s |
| 2026-06-20 | 1.36 s | 82 ms | 0.020 | 1.34 s | 800 ms |
| 2026-06-13 | 1.26 s | 81 ms | 0.030 | 1.25 s | 654 ms |
| 2026-06-06 | 1.25 s | 87 ms | 0.030 | 1.23 s | 638 ms |
| 2026-05-30 | 1.43 s | 81 ms | 0.030 | 1.37 s | 796 ms |
Page weight
| Metric | Current | Previous | Change | Best | Worst | Trend |
|---|---|---|---|---|---|---|
| Page Weight | 493.1 kB | — | — | 493.1 kB | 493.1 kB | |
| Requests | 14 | — | — | 14 | 14 | |
| Third-party Weight | 0 B | — | — | 0 B | 0 B | |
| Third-party CPU | 0 ms | — | — | 0 ms | 0 ms | |
| Unused JS | 0 B | — | — | 0 B | 0 B | |
| Unused CSS | 0 B | — | — | 0 B | 0 B |
By resource type
Page health
| Metric | Current | Previous | Change | Best | Worst | Trend |
|---|---|---|---|---|---|---|
| Main Thread Work | 885 ms | — | — | 885 ms | 885 ms | |
| Long Tasks | 5 | — | — | 5 | 5 | |
| DOM Elements | 86 | — | — | 86 | 86 | |
| Axe Violations Violating nodes from a full axe run — stricter than Lighthouse's subset | 4 | — | — | 4 | 4 | |
| A11y Failures | 3 | — | — | 3 | 3 | |
| A11y Failing Nodes | 5 | — | — | 5 | 5 |
Main thread work
Axe violations axe-core 4.13.0, full rule set
4 violating nodes across 3 rules, 233 passing. This is a standalone axe run, stricter than the subset Lighthouse folds into its score above — and it is the second tiebreaker in the ranking.
-
serious
color-contrast— Elements must meet minimum color contrast ratio thresholds 2 nodes -
moderate
landmark-unique— Landmarks should have a unique role or role/label/title (i.e. accessible name) combination 1 node -
moderate
meta-viewport— Zooming and scaling must not be disabled 1 node
Accessibility failures 3 of 18 audits
Tracked as a count, not just the score — the weighted score is coarse enough that you can ship a broken component and barely move it.
-
color-contrast— Background and foreground colors do not have a sufficient contrast ratio. 2 nodes -
target-size— Touch targets do not have sufficient size or spacing. 2 nodes -
meta-viewport— `[user-scalable="no"]` is used in the `<meta name="viewport">` element or the `[maximum-scale]` attribute is less than 5. 1 node
Hygiene
Changes rarely — which is exactly why a change is worth noticing.
Measurement log
Every stored run for this URL, newest first. Failures are kept as records — "this site was down on Tuesday" is data too.
| When | Perf | LCP | CLS | TBT | Weight | Runs | Spread | Bench | Took |
|---|---|---|---|---|---|---|---|---|---|
| Aug 21, 2026, 9:35 AM UTC | 99 | 982 ms | 0 | 102 ms | 493.1 kB | 3/3 | ±2 | 2,396 | 28.5s |
Embed this score
Live below, then the markup that produces it. Drop that on any page to show
worldwideweb.cern.ch's scores, updated whenever this instance
re-measures — more about the component. Don’t forget to bundle the speedlify-score.js component code into your site!
<speedlify-score speedlify-url="https://zachleat.github.io/speedlify2/" url="https://worldwideweb.cern.ch/"></speedlify-score>