How to use Website Speed Test Tools
- Paste or load a Lighthouse JSON report (or paste it) into Website Speed Test Tools.
- Click Read report — Website Speed Test Tools processes everything on your device.
- Read the category scores and Core Web Vitals that Website Speed Test Tools lays out for you.
About this tool
Website Speed Test Tools is a static, client-side tool with no backend. Export a report from Chrome DevTools or PageSpeed Insights and load the JSON into Website Speed Test Tools to see the scores locally.
It shows category scores and Core Web Vitals such as LCP, CLS and TBT, read straight from the JSON. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
What is Website Speed Test Tools for?
Use Website Speed Test Tools to check your input without installing anything; everything happens client-side.
Does Website Speed Test Tools cost anything?
No — Website Speed Test Tools is completely free, with no sign-up and no hidden limits.
Is my input private in Website Speed Test Tools?
Yes — your input never leaves your device; Website Speed Test Tools does all the work in your browser.
What file does Website Speed Test Tools read?
Export a Lighthouse or PageSpeed Insights JSON report and load it into Website Speed Test Tools; it surfaces the scores and Core Web Vitals locally.
Does Website Speed Test Tools work on mobile?
Yes — Website Speed Test Tools is just a web page and runs on any modern browser, including phones and tablets.