Gets the amount of storage space, in bytes, used one or more items being stored in the storage area.

This is an asynchronous function that returns a Promise.


var gettingSpace =<storageType>.getBytesInUse(
  keys                      // null, string, or array of strings

<storageType> will be one of the writable storage types — storage.sync or storage.local.


A key (string) or keys (an array of strings) to identify the item(s) whose storage space you want to retrieve. If an array is passed in, 0 will be returned. If you pass null or undefined here, the function will return the space used by the entire storage area.

Return value

A Promise that will be fulfilled with an integer, bytesUsed, representing the storage space used by the objects that were specified in keys. If the operation failed, the promise will be rejected with an error message.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxOperaFirefox for Android
getBytesInUseChrome Full support YesEdge Full support 14Firefox No support NoOpera Full support 33Firefox Android No support No


Full support  
Full support
No support  
No support

This API is based on Chromium's API. This documentation is derived from storage.json in the Chromium code.

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.