Browser Storage Speed Test
This test writes and reads data in your browser’s private storage and reports sequential speed and small-file operations per second. It cleans up after itself, and nothing leaves your device.
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About this tool
What it measures
The test writes a file of 16, 64 or 128 MB and reads it back, then creates and reads 200 small 4 KB files. It uses the Origin Private File System where your browser supports it, and IndexedDB otherwise. Sizes that would not fit in the storage your browser allows are turned off.
Privacy and cleanup
Test data is random bytes created on your device. The files live in this site’s private storage area and are removed when the test finishes, even if you stop it or an error occurs.
How to read the results
This measures the browser’s storage layer, including operating system caching. It is not a raw SSD or hard drive benchmark, and it will not match tools such as CrystalDiskMark. Read speeds often look high because recently written data is still in memory.
The small-file figure is often the more telling one: it shows how well storage handles many tiny operations, which matters for app startup and web apps.
Frequently asked questions
Why does the test refuse a size?
Browsers limit how much storage a site may use, and private windows allow much less. The test keeps twice the test size free, so pick a smaller size.
Is this the speed of my SSD?
Not directly. The browser, the file system and the operating system cache all sit in between.
Does it leave files behind?
No. Everything is deleted at the end of the run.
Why is read faster than write?
The operating system caches recently written data in memory, so reads often return from RAM. Run it a few times and compare.
Does it leave files on my computer?
The test files live in the browser's private storage and are removed when the test finishes.
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