worldwideweb.cern.ch
Data from Aug 21, 2026, 9:35 AM UTC 2d old
Built Awesome #667 · 1 measurement · since Aug 21, 2026
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 observed, unthrottled
A flat LCP number tells you something regressed. The subparts tell you whether it was the server, resource discovery, the download, or rendering.
Measured on the trace before throttling is modelled, so these are real durations that will not sum to the 982 ms above — that figure is a simulation of the same load on a slow phone and connection. Read these for the proportions: which phase dominates.
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 kB | — | — | 493 kB | 493 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 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 speedlify2-score.js component code into your site!
<speedlify2-score speedlify-url="https://www.speedlify.dev/" url="https://worldwideweb.cern.ch/"></speedlify2-score>