Every file your page
makes a visitor download.
We fetch the page, pull out every stylesheet, script, image and font it references, download them all and weigh the result. Total megabytes, a full waterfall, and the fixes ranked by the bytes each one actually saves.
We download your page, then weigh it
Not a lookup, not an estimate. Every file, fetched in parallel, measured as a browser would receive it.
Total megabytes
The real transferred size of every stylesheet, script, image and font, with the compression a browser would actually receive.
A full waterfall
Every file listed heaviest first, with its size, type, compression state and whether it blocks the page from appearing.
Image analysis
We read the real pixel dimensions out of each image and compare them to the size it is displayed at. Serving a 3000px photo into a 400px box is the most common waste there is.
Compression and caching
Which files arrive uncompressed, which are unminified, and which have no cache lifetime so repeat visitors download them all over again.
Third-party weight
How much of your page belongs to somebody else. That portion cannot be optimised, only removed, which makes it a different kind of decision.
Savings in bytes
Each fix carries the actual saving where one can be computed. Where it cannot, we say so instead of printing a made-up number.
Three things about speed scores
Including the reason this tool does not show you a Core Web Vitals number.