Install Text Size Adjuster

Text Size Adjuster is a Firefox add-on. It works on your computer and on your Android phone.

Text Size Adjuster is waiting for Mozilla's review before it appears on Firefox Add-ons. Until then, you can install it straight from this site. It's the same add-on, signed by Mozilla.

On your computer

1. Open this page in Firefox and click Download Text Size Adjuster.
2. Firefox says it prevented this site from installing software. Click Continue to Installation.
3. Click Add when Firefox asks.

If the file downloads instead of installing (for example in another browser), drag it onto a Firefox window.

You need Firefox 140 or newer. Firefox asks for permission to access your data for all websites. Text Size Adjuster needs that to resize the text on the pages you visit, and collects nothing.

From version 1.4.0 on, Firefox keeps it up to date: it checks for new versions and installs them itself. Earlier versions (1.1.0) don't update; if you have one, install it once more from the link above to get updates from then on. To see your version, open the add-on's Options.

On your Android phone

Firefox for Android only installs add-ons that aren't on Firefox Add-ons after you turn on a hidden option once. The steps are in installing on Android. Once Text Size Adjuster is on Firefox Add-ons, you can install it from there instead:

1. Open Firefox, tap the ⋮ menu, then Extensions (or Add-ons).
2. Find Text Size Adjuster in the list or search, and tap +.
3. Tap Add when Firefox asks.

How to use it

• Zoom in on a page (pinch with two fingers, or Ctrl/Cmd + + on a computer) and a small round control appears in a corner. Tap + to make the text bigger and − to make it smaller. ↺ goes back to normal, ⚙ opens the settings, and × hides the control on that page.
• You can also adjust the size any time from the Text Size Adjuster button in Firefox's toolbar (or the extensions menu on Android) — no zooming needed.
• Your chosen size is remembered for each website. Next time you visit, it's already applied.

Settings

Open the add-on's Options (from the ⚙ on the control, from the Text Size Adjuster button → Options…, or from Firefox's Add-ons page). There you can:

• choose which corner the control sits in;
• choose to show the control always, instead of only after you zoom in;
• turn off remembering sizes automatically — then size changes last until you reload, and you can keep a site's size with the Remember this site button that appears when you click the Text Size Adjuster button;
• see the list of sites where you've changed the text size, and remove any of them to put that site back to normal.

Curious how this is different from your phone's own text-size setting, and why you don't have to scroll sideways? See how it differs. Some things it can't change are listed under what it can't fix.