How to calculate/predict width after a browsers zoom?

Question

Specifically, how do I predict/calculate the effect any of the browsers' zoom will have, for example, on width:950px? Are there any tools I can use to determine the new widths?

edit: If I have a 950px div that is visually rendered 875px in, say, chrome, I could say chrome reduces fixed widths by approx. 92.1% after one crtl-. (950*.921= approx .875).

Answer 1

Try Firebug

Its an excellent plugin for Firefox, which lets you view variety of parameters. You could play around with it and it would probably solve your problem.