Theme Font & Size Changer


Theme Font & Size Changer Project Image

Theme Font & Size Changer is a simple browser tool that lets you change the font size and font family of Firefox. It is especially valuable tool for visually impaired people and wide screen users.


There are three places that you can manage the global font size and font family of Firefox via Theme Font & Size Changer. Add-on Bar icon, toolbar button and Tools menu option. All font size and font family changes are instantly applied and they are saved permanently and through sessions.

Different from add-ons that enlarge and reduce text on web pages, Theme Font & Size Changer changes the font size and font family in all windows, menus, toolbars, etc within Firefox itself.

It was initially created to be an accessibility aid for persons with visual impairments and for those without perfect eyesight, but it’s also useful for Firefox users with high monitor resolution settings and wide screens.

While Theme Font & Size Changer was written to be used with Firefox default theme, it does work with other non-default themes, but you may come across issues where some elements within Firefox retain the (non-default) font size setting that the theme developer chose for their theme.

There are three places that you can manage the global font size and font family of Firefox via Theme Font & Size Changer:

• Add-on Bar Button: Click on the Theme Font & Size Changer button to open up Theme Font & Size Changer settings panel.

NOTE: Add-on Bar resides at the bottom of the Firefox window. Add-on Bar is the old status-bar. If Add-on Bar is not visible, you should activate it. To do so, choose View menu from Firefox Menu Bar and hover over the Toolbars option and click on the Add-on Bar option if there is no tick. If you are Windows 7 user, you should click on the orange Firefox button at the top of the window and hover over the Options and click on the Add-on Bar option if there is no tick.

• Tools Option: Choose Tools menu from Firefox Menu Bar and click on the Theme Font & Size Changer option. It will open up Theme Font & Size Changer settings panel.

• Toolbar Button: It is optional so it is not visible as default. If you want to place a Toolbar Button, right click on a toolbar button like Home Button, then choose Customise option. A window will pop up. Find the Theme Font & Size Changer button, then click and drag the Theme Font & Size Changer button in the toolbar of your choice and drop the button. Clicking on this Theme Font & Size Changer button will open up Theme Font & Size Changer settings panel.

In Theme Font & Size Changer settings panel, Font section provides fonts currently installed on your operating system. With this option set, you will be able to fine tune your font family of Firefox theme.

In Size section, simply select a font size value (from 6 to 80 pixels) and the changes will be applied instantly and globally.

No known compatibility issues with the following themes:

NASA Night Launch
Kempelton
Kempelton Large
Qute
Mostly Crystal
Silvermel
Walnut for Firefox
Ambient Fox Xyan
Themes by Aaron Spuler

There are no known compatibility issues with Personas skins.

Special thanks to Ken Saunders for the priceless contribution and testing efforts.

Install Theme Font & Size Changer


26 Responses to “Theme Font & Size Changer”
  1. James Timothy Riley says:

    This is a fantastic app. This will give me the tools to sharpen up my correspondence, brighten up my emails, and just have fun doing it. Thanks all!! Tim

  2. angelika maria hernandez says:

    LA MAMASOTAA

  3. jack213 says:

    Love this app!! My vision is terrible so i really enjoy this app. I also like how the font matches my Modern theme!!

  4. [...] Uno strumento che permette di modificare queste impostazioni è sicuramente l’add-on “Theme Font & Size Changer“. Questra estensione per Firefox consente di modificare semplicemente i caratteri, le [...]

  5. Gonzalo says:

    Just installed it today and working great so far, will keep on testing it, congratulations and thanks so much for your great work here.

  6. Chris Colborne says:

    Following the recent Firefox Update (22.0) this Add – on has proved to be Excellent in changing the Defaults Fonts back to how I like them.
    A+++++