Web/API/StorageEstimate

Secure contextThis feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The StorageEstimate dictionary is used by the StorageManager to provide estimates of the size of a site's or application's data store and how much of it is in use. The estimate() method returns an object that conforms to this dictionary when its Promise resolves.

These values are only estimates for several reasons, including both performance and preventing storage capacity data from being used for fingerprinting purposes. See the individual property pages for details.

Properties

quota Secure context

A numeric value in bytes which provides a conservative approximation of the total storage the user's device or computer has available for the site origin or Web app. It's possible that there's more than this amount of space available though you can't rely on that being the case.

usage Secure context

A numeric value in bytes approximating the amount of storage space currently being used by the site or Web app, out of the available space as indicated by quota. Unit is byte.

usageDetails Secure context

A dictionary containing a breakdown of usage by storage system.  All included members will have a usage greater than 0 and any storage system with 0 usage will be excluded from the dictionary.  

Specifications

Specification	Status	Comment
StorageThe definition of 'StorageEstimate' in that specification.	Living Standard	Initial definition.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
StorageEstimate	Chrome Full support 52	Edge Full support ≤79	Firefox Full support 51	IE No support No	Opera Full support 42	Safari ?	WebView Android Full support 52	Chrome Android Full support 52	Firefox Android Full support 51	Opera Android Full support 42	Safari iOS ?	Samsung Internet Android Full support 6.0
quota	Chrome Full support 52	Edge Full support ≤79	Firefox Full support 51	IE No support No	Opera Full support 42	Safari ?	WebView Android Full support 52	Chrome Android Full support 52	Firefox Android Full support 51	Opera Android Full support 42	Safari iOS ?	Samsung Internet Android Full support 6.0
usage	Chrome Full support 52	Edge Full support ≤79	Firefox Full support 51	IE No support No	Opera Full support 42	Safari ?	WebView Android Full support 52	Chrome Android Full support 52	Firefox Android Full support 51	Opera Android Full support 42	Safari iOS ?	Samsung Internet Android Full support 6.0

Legend

Full support  

Full support

No support  

No support

Compatibility unknown  

Compatibility unknown

See also

• Storage API
• StorageManager
• StorageManager.estimate()
• navigator.storage

StorageEstimate by Mozilla Contributors is licensed under CC-BY-SA 2.5.