Theme Font & Size Changer for Firefox

Theme Font & Size Changer: Firefox Add-on

Firefox (Vista) default theme
Firefox toolbars default theme

Firefox (Vista) default theme with the Diavlo Bold font and the font size at 28 pixels
Firefox toolbars with 26 pixel text

About - Using - Screen Shots - Credits

About Theme Font & Size Changer

There are many Firefox add-ons that provides you with the means to enlarge and reduce text on web pages. Theme Font & Size Changer allows you to change the global font (using your sytem's fonts) and font size for Firefox itself meaning for all windows, menus, toolbars, etc.
It was created to be an accessibility aid for persons with visual impairments and for those without a perfect visual acuity, but it's also useful for Firefox users with high monitor resolution settings and wide screens.
Theme Font & Size Changer is also available for Thunderbird and SeaMonkey.

While Theme Font & Size Changer was initially designed to be used with Firefox's default theme, it does work with other Firefox themes but you may come across some compatibility issues. For example, some elements within Firefox may retain the (non-default) font size setting that the theme developer chose for their theme.
There are no known compatibility issues with Personas.

Theme Font Size Changer logo Get Theme Font & Size Changer

Using Theme Font & Size Changer

There are several ways to access Theme Font & Size Changer's menu to choose a font and font size.

  • Firefox Menu Bar showing: Tools > Theme Font & Size Changer
  • Firefox Menu Bar hidden: Alt+T > T or Alt+T > Theme Font & Size Changer
  • Toolbar Button: Right click on a toolbar > Customize > drag the Theme Font & Size Changer button to the toolbar of your choice.
  • Add-on Bar Button: Click on the Theme Font & Size Changer button.

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Theme Font & Size Changer access options

Simply select a font size value and a font and it will be applied instantly and globally. A "Normal" (default) value is also provided for both the font and font size so that you can quickly reset your settings back to default ones.
Tip: You can cycle through fonts to see how each one would look like when applied by hitting the up or down arrows on your keyboard when the font field is highlighted. Same applies to font sizes. Some Dingbats, Wingdings, etc, may temporarily freeze up Firefox while they are being loaded. It's best just to skip past them quickly.

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Theme Font & Size Changer menu

Hide the Add-on Bar Button:
Go to the Add-ons Manager > Extensions > Theme Font & Size Changer > Options > Check "Hide the statusbar icon"

Theme Font & Size Changer preferences

Theme Font Size Changer logo Get Theme Font & Size Changer

Screen Shots

Click on any image below to enlarge it.
You can cycle through all of the images by using your keyboard's right and left arrow keys, or by clicking on either the right or left hand side of an image (once it's enlarged).

Thme Font Size Changer logo Get Theme Font & Size Changer


Very special thanks to Baris Derin for writing Theme Font & Size Changer.
It is an extension that I first saught out a developer for nearly 5 years ago and Baris is the one who finally stepped up to the plate to get it made.

Be sure to check out these other great add-ons by Baris Derin.

"Reader is the ultimate Reader tool that brings the Safari 5 Reader features to Firefox and helps you read more of the web by transforming text on any website using fonts, colors, and layouts of your choosing."
Personas Rotator
Automatically rotates your Personas Favorites.
Browser Backgrounds
Install and display full sized backgrounds (wallpapers) in Firefox from the community site, or use your own.
Wallpaper Rotator
Firefox add-on that allows you to change and rotate your desktop wallpapers. You can get wallpapers from the community site, or use your own.
View all Firefox add-ons by Baris Derin.

Theme Font & Size Changer palette icon is based on the Kempelton Theme.svg icon by Arvid Axelsson.