In the gtk-3.0.css file you can change the font throughout the program. If you want to do something globally, you can add this and change to your reqirements:

/* Application wide font setting */
* {
font: 18px arial;
}

This seems like an easy deliverable and should be addressed as soon as possible. This is a major accessibility option that will prevent people from using, or continue to use your product.

As many have said before bring able to Ctrl+Scroll or Ctrl++ or Ctrl-- is the way to go as most applications come out of the box with this ability. Worst case add it to preferences.

It would be great if there were a feature similar to in a web browser, where I can press 'ctrl' and move the mouse wheel forward and back to change the font size. thanks

Yes. Fonts are too small for me.

I've got a 27" 2560x1440 display and the font size is wreaking havoc with my 45-year-old eyes. Please tell me which file I have to edit to get the display font up to a readable size. I'm not 25 anymore!

with 4.2 report font changed and shrank to where is is no longer readable

We were just discussing this in the gnucash user list. Even access to stylesheets would help, although not everyone can handle stylesheets. This is important to those of us who may be older or have accessibility issues. It has also been pointed out that accountants may not be all that tec-savvy.

I was looking forward and installed 3.5. I can't stand the smaller font and hairline thin look of the fonts, or in other words anything that is entered. Sadly I was forced to uninstall and reinstall 3.4.

Running 3.5 here and still can't adjust the screen font size. On Windows 10, can I add a .css entry to fix this?

The newest rel has caused the font size to be reduced. I need to increase font size to make it usable again.

The "Select Theme" tool can be found under the Windows start menu:
Start->All Programs->GnuCash->Select Theme

I am using Gnucash version 2.6.5 (on Windows 7) . I cannot find the "select theme" tool. Please tell where is located (specifically). - Thanks

"Dean Gibson commented · February 14, 2015 22:34 ·

Try running the "Select Theme" tool (separate executable) that is installed w/ GnuCash"

Try running the "Select Theme" tool (separate executable) that is installed w/ GnuCash

Font size could even be changable by using some kind of shortcuts, similar to browsers:
STRG+
STRG-

Me too! I went back to version 2.4.8.

Can't believe something as basic as this isn't already in preferences, the tiny font is far too small for me to see clearly too!