What does half a pixel mean in the font-size CSS property?

Question

I\'m currently working on a website redesign and I\'m receiving a list with the required changes from an agency.

The header menu of the site currently has the follow

Answer 1

I think there is a difference. You forgot about the Zoom level of the page.

Example :

aAa


aAa


aAa


aAa


aAa

If we zoom to 500%, we can see there is a difference:

I think your browser has to round it because half pixels (real pixels) don't exist.

Zoom 100% :

Round(12 * 1.00) = 12

Round(11.5 * 1.00) = 12

Zoom 500% :

Round(12 * 5.00) = 60

Round(11.5 * 5.00) = 58