Text Size Adjuster

Make a page's text bigger or smaller with one tap — without zooming the whole page or scrolling sideways.

Install See it in action

Learn more

• How this differs from your browser's zoom/accessibility settings
• What this can't fix (and why)

Run a website?

Give every visitor the same +/− control with a single script tag — see how, or try the demo page that does exactly that.

Advanced installation

For technical users who want to try unsigned builds, or use it outside Firefox:

• As a userscript (Tampermonkey/Violentmonkey; also works in Chrome) — no signing needed, but doesn't remember sizes per site
• The extension, installed manually — temporary load, or unsigned builds on Firefox Developer Edition, Nightly or ESR