Storage quota viewer
The page asks your browser how much storage is used and the quota it allows for this site, and measures the Web Storage of this site. Everything is read locally; no numbers are sent anywhere.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Open the page; the numbers load by themselves. Press Refresh after using other tabs of the site to update them.
- Read Used, Quota and the share of the quota in the bar.
- Look at Persistent storage. If it says No, the button Request persistent storage asks the browser to keep this site’s data.
- The last block shows how big localStorage and sessionStorage are for this site.
How it works
The page calls navigator.storage.estimate() for usage, quota and, where available, a breakdown, and navigator.storage.persisted() for the persistence flag. For Web Storage it goes through every key and counts 2 bytes for each character of the key and the value.
Worked example
A localStorage with one key “theme” (5 characters) and the value “dark” (4 characters) takes (5 + 4) × 2 = 18 bytes. With usage 52 428 800 bytes and quota 2 147 483 648 bytes, the share is about 2.4 %, and the page shows 50 MB of 2 GB.
Tips
- In a private window the quota can be much smaller than in a normal one.
- Clearing site data is done in the browser’s settings, not on this page.
Frequently asked questions
What do usage and quota mean?
Usage is the estimated space used by this site in the browser, across IndexedDB, cache storage and similar. Quota is the maximum the browser will let the site use. Both come from navigator.storage.estimate and are estimates.
What is persistent storage?
By default the browser may delete a site's data when the device runs low on space. Persistent storage asks the browser not to. The browser decides whether to grant it; it may ask you or decide by itself from how you use the site.
How is the localStorage size calculated?
Each key and each value is a string of UTF-16 characters, and the page counts 2 bytes per character. That is how browsers typically count localStorage, which is often limited to around 5 MB per site, a common limit but not a guarantee.
Why is there no breakdown?
Only some browsers report how usage splits into IndexedDB, caches and service workers. If yours does not, you will see a note instead.