Why is text rendered with a greater font-size in Opera?

Question

I\'m working on an HTML page that needs to be more or less pixel-perfect, and I noticed that in Opera 10, fonts are rendering larger than they do in other browsers, even tho

Answer 1

I came across this thread when I was having similar issues with Opera 11.10 on Windows 7 x64.

Opera was defaulting to using 20px as the body font-size (rather than 16px which is what other browsers use). This persisted even after uninstalling, deleting Opera preferences and re-installing. It turns out that Opera will honor your system font-size preferences (set under 'Control Panel\Appearance and Personalization\Display' on Win7) for rendered website text whereas other browsers (I tested FF4, Chrome 11, Safari 5, IE 9) do not. My system font size was set to 125% which explains the 20px. Once I set my system font zoom to 100%, Opera behaved the same as the others.

I'm not sure which behavior is more correct (In a way, it's nice that Opera honors my font choice) but since since other browsers do not do the same, it is "unexpected". I don't have a Mac to test but perhaps MacOS has a similar system font preference?