What WebPageTest measures
WebPageTest loads your page from a real browser on real hardware in a location you choose, records the whole thing on video, and reports every request with full timing detail. It runs the test more than once so you can compare a first visit against a repeat visit with a warm cache. The filmstrip shows frame by frame what a visitor watched while the page assembled itself.
How to read your result
The filmstrip is the most honest view of your site that exists, because it shows the experience rather than a number. Scrub along it and find the moment the page becomes useful, then look at what the waterfall was doing right before that moment. The repeat view tells you whether your caching is set up properly: if the second load is barely faster than the first, browsers are being told to re-download things they already have.
What to change first
If the filmstrip shows a long blank white period before anything appears, the problem is render blocking resources in the head of your page, usually stylesheets and fonts. If the page paints early but then jumps around, the problem is images and ads without reserved space.
Common questions
- Why does WebPageTest ask me to pick a location and browser?
- Distance to the server is a large part of load time, so a test from Virginia tells a London business very little. Pick the location closest to where most of your visitors are.
- What is the difference between First View and Repeat View?
- First View is a brand new visitor with an empty cache. Repeat View is someone coming back who already has your files. A big gap between them means your caching is working.
- Is WebPageTest free?
- Yes for the standard public tests, though busy times put you in a queue. Paid plans skip the queue and add private test locations.
Related tests
Run this alongside every other test in Website Speed Tests, or start from the full list of website testing tools.