Zooms the specified tab.

This is an asynchronous function that returns a Promise.


var zooming = browser.tabs.setZoom(
  tabId,           // optional integer
  zoomFactor       // number


integer. The ID of the tab to zoom. Defaults to the active tab of the current window.
number. The new zoom factor. Use a value of 0 here to set the tab to its current default zoom factor. Otherwise, this must be  a number between 0.3 and 3, specifying a zoom factor.

Return value

A Promise that will be fulfilled with no arguments after the zoom factor has been changed. If the tab could not be found or some other error occurs, the promise will be rejected with an error message.

Browser compatibility

ChromeEdgeFirefoxFirefox for AndroidOpera
Basic Support (Yes) No45 No (Yes)


Set the zoom factor for the current tab to 2:

function onError(error) {
  console.log(`Error: ${error}`);

var setting = browser.tabs.setZoom(2);
setting.then(null, onError);

Set the zoom factor for the tab whose ID is 15 tab to 0.5:

function onError(error) {
  console.log(`Error: ${error}`);

var setting = browser.tabs.setZoom(16, 0.5);
setting.then(null, onError);

Example extensions


This API is based on Chromium's chrome.tabs API. This documentation is derived from tabs.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.

Document Tags and Contributors

 Contributors to this page: wbamberg, Makyen
 Last updated by: wbamberg,