Speed 10 tools
Lab and field speed tests, Core Web Vitals history, image and code checks, for one URL or fifty at once. Start with the website speed test; the other tools go deeper on what it finds.
Runs the website speed test. Every other tool on this page opens with the same address filled in.
In the full report
These tools are the Speed module, split out.
The full report runs them together with a score, the history of every earlier check and the fixes in order of impact.
Rings show a sample report, not your site.
Run a free reportSpeed & Core Web Vitals
- Website speed testMobile and desktop, lab + fieldScore, Core Web Vitals, ranked fixes
- Core Web Vitals checkerReal-user LCP, INP and CLSGood, needs work or poor per metric
- Core Web Vitals history40 weeks for any siteWeekly chart against the thresholds
- Website speed comparisonNewUp to 5 sites side by sideSide-by-side table, winner per metric
- Bulk PageSpeed InsightsNewUp to 50 URLsScore per URL, sortable, CSV export
Server & delivery
- TTFB testServer response timeFirst-byte time from 3 sources
- HTTP/2 & HTTP/3 testProtocol and compressionProtocol, compression and caching
Images & code
- Image size checkerOversized images and old formatsWeight per image, total image bytes
- Image compressorRuns on your computerWebP and AVIF, in bulkSmaller WebP or AVIF files
- Unused CSS/JS checkerNewCode you ship but don't useUnused bytes per file, time saved
“Runs on your computer” tools never upload your files or text.
Fix what the tools find
All 52 Speed & Core Web Vitals guides →- 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 - Best practices13 min read
Brotli compression: gzip vs Brotli and how to enable it
Brotli compression shrinks HTML, CSS and JavaScript by around 80 % before they leave your server, a few percent better than gzip. What to compress, which to pick, and configs for nginx, Apache, Caddy and Cloudflare.Updated 4 Oct 2026
Questions about speed tools
Why do lab and field numbers differ?
Lab numbers come from one Lighthouse run on a simulated mid-range phone with a throttled connection. Field numbers are what real Chrome visitors measured over the last 28 days, from the Chrome UX Report. Google ranks on the field numbers; the lab run tells you why they are what they are.
Which speed tool should I start with?
The website speed test. It shows the score, the three Core Web Vitals and the fixes worth the most. Then go deeper where it points: the TTFB test for a slow server, the image size checker for heavy images, the unused CSS/JS checker for code you ship but never run.
Why is my mobile score lower than desktop?
The mobile test simulates a mid-range phone on a slow 4G connection, so every script and image costs more time. Most visitors are on phones and Google indexes the mobile version, so the mobile number is the one to work on first.
Can I test many pages at once?
Yes. Bulk PageSpeed Insights runs up to 50 URLs and exports the scores as CSV, the speed comparison puts up to 5 sites side by side, and the Core Web Vitals history shows how a site did week by week.
Want all of them at once?
The full report runs the speed, SEO, security, accessibility, schema and social checks together.