Firefox: Zoom in on only one tab

written by Sue Frantz | December 17, 2020

I have three screens, and one of them is relatively small. Sometimes I’ll have browser tabs open on all three screens. For the tab that’s open on the smaller screen, I want to zoom in to make the text bigger.

CTRL + will zoom in

CTRL – will zoom out

CTRL+0 will reset the zoom to the default.

Chrome treats each tab as its own individual entity. Zooming in on one tab does not affect the zoom settings on another tab.

With Firefox, however, zoom in on one tab, and you zoom in on them all. These days, Firefox is my primary browser, and with my one small screen, I only want to zoom in on the tab that’s open in that screen, and not the tabs that are open in my larger monitors.

The solution is provided by Mozilla (the makers of Firefox) support.

  1. type about:config in your address bar and press enter
  2. if Firefox asks you, say you’ll be careful
  3. search this string browser.zoom.siteSpecific (if it doesn’t exist, create one, it’s a boolean string)
  4. set it to false (rightclick > “Toogle”).

Ta da! Now I can zoom in on only one tab, and all of my other tabs remain unchanged.