Speed & Core Web Vitals
The metrics Google measures on real visitors, what slows a page down and how to make it fast.
- Speed13 min read
PageSpeed score: how to read it and what counts as good
A PageSpeed score is a 0-100 summary of five lab metrics from one simulated visit on a phone: 90 or more is good, 50-89 needs improvement, under 50 is poor. Here is what the number means, why it moves and what to fix first.Updated 15 Oct 2026 - Speed16 min read
Reading a waterfall chart and filmstrip: where the seconds go
A request waterfall shows every file a page loads and when; the filmstrip shows what the visitor saw meanwhile. Learn the anatomy of a bar, the six patterns behind most slow pages, how to match frames to metrics, and what to fix first.Updated 15 Oct 2026 - Speed14 min read
HTTP/2 vs HTTP/1.1: multiplexing, header compression and what changes for your site
HTTP/2 vs HTTP/1.1: HTTP/2 sends every file of a page over one connection at once and compresses headers, where HTTP/1.1 queues files six at a time. What changes, what does not, and what happened to server push.Updated 4 Oct 2026
Fix pages
Core Web Vitals and lab metrics
4 of 8- How to fix Largest Contentful Paint (LCP)High impact.Fixes
lcp+11 min - How to fix Interaction to Next Paint (INP)High impact.Fixes
inp+11 min - How to fix Cumulative Layout Shift (CLS)High impact.Fixes
cls+21 min - How to improve First Contentful Paint (FCP)High impact.Fixes
fcp+11 min
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- How to reduce Time to First Byte (TTFB)High impact.Fixes
crux-ttfb+11 min - How to reduce Total Blocking Time (TBT)High impact.Fixes
tbt1 min - What Speed Index means and how to improve itHigh impact.Fixes
speed-index1 min - How the Lighthouse performance score worksFor information.Fixes
lighthouse-performance-score1 min
Images
3 of 3JavaScript and the main thread
4 of 5- How to reduce unused JavaScriptMedium impact.Fixes
unused-js1 min - How to control third-party script weightMedium impact.Fixes
third-party-weight1 min - How to reduce an excessive DOM sizeMedium impact.Fixes
dom-size+11 min - How to avoid long main-thread tasksMedium impact.Fixes
long-tasks1 min
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CSS and fonts
3 of 3Server, compression and caching
3 of 3Check all 33 at once
The Website speed test runs every check on this page against your site.