Increase the String pref layout.css.devPixelsPerPx from 1.0 to 2.0 in 0.1 or 0.05 steps to adjust the size of all fonts and other elements in Firefox.
The layout.css.devPixelsPerPx pref is a String value parsed to a float and allows to fine tune the dimensions of all elements (user interface and web pages) more precisely (resolution 0.1 or 0.05).
You can use values between 0.05 and 1.0 to reduce elements in size or use values greater than 1.0 to magnify and make elements larger (percentage divided by DPI, % / DPI).

You can use an extension to set a default font size and page zoom on web pages.

• Default FullZoom Level: https://addons.mozilla.org/firefox/addon/default-fullzoom-level/
• NoSquint: https://addons.mozilla.org/firefox/addon/nosquint/

Thank-you for the reply!

As I've been building webites (using a drag and drop editor) and renting cross-browser testing tools as needed, I'm curious to know:

The way Firefox displays out of the box for me, it is the way it would for anyone then (as you are not saying I've messed up a personal setting here)?

It would be good to know that this is 'just the way Firefox is' (without adjustment for everyone viewing my website).

Thanks again, sss

If the Firefox user interface is affected as well and not only the browser area that displays web pages then something else is wrong.
You may either have changed the DPI setting in Windows or otherwise changed settings to make this happen.

I don't know where these settings are in Windows 8.

• http://www.google.com/search?q="Make+text+and+other+items+larger+or+smaller"

Modifying the above posted pref makes it possible to adjust the dimensions of all elements, both the user interface and the browser area.

The only change I've made in Windows 8 regarding size/readability is in the Display Settings, where I changed the size of the desktop items to 150% from the default of 125%. (In the Ease of Use/Accessability center, I made no visual changes). My pc is using it's native resolution of 1920x1080.

IE and Chrome both have larger 'out of the box' UI's and webpages.

This is useable by zooming in each time I open a new page and squinting at the UI. If I can't find out what's wrong, I'll just install an add-on. But I enjoy checking my webpages in all 3 browsers - the way others would see them without add-ons, so would be nice to know why FF is smaller. If that's normal, fine - but would just like to be sure.

Do you think it's my resolution and Chrome/IE are adjusting to it somehow?

Thanks Again, sss

You can set the layout.css.devPixelsPerPx pref to 1.5 to increase all items in Firefox by 150%

• http://kb.mozillazine.org/about:config

Thanks for your help cor-el.

I've just installed NoSquint and it works perfectly for web; pages. Then I found a theme with larger icons in 'complete themes' - there are a number of them.

Guess I was hoping to understand why only FF was smaller, (not just fix the problem) - however, fixing it is very nice too - thanks!