Font Size Conversion Chart

Font Size Conversion Chart

Points	Pixels	Ems	Percent	Keyword	Default sans-serif
6pt	8px	0.5em	50%		CSS Tricks
7pt	9px	0.55em	55%		CSS Tricks
7.5pt	10px	0.625em	62.5%	x-small	CSS Tricks
8pt	11px	0.7em	70%		CSS Tricks
9pt	12px	0.75em	75%		CSS Tricks
10pt	13px	0.8em	80%	small	CSS Tricks
10.5pt	14px	0.875em	87.5%		CSS Tricks
11pt	15px	0.95em	95%		CSS Tricks
12pt	16px	1em	100%	medium	CSS Tricks
13pt	17px	1.05em	105%		CSS Tricks
13.5pt	18px	1.125em	112.5%	large	CSS Tricks
14pt	19px	1.2em	120%		CSS Tricks
14.5pt	20px	1.25em	125%		CSS Tricks
15pt	21px	1.3em	130%		CSS Tricks
16pt	22px	1.4em	140%		CSS Tricks
17pt	23px	1.45em	145%		CSS Tricks
18pt	24px	1.5em	150%	x-large	CSS Tricks
20pt	26px	1.6em	160%		CSS Tricks
22pt	29px	1.8em	180%		CSS Tricks
24pt	32px	2em	200%	xx-large	CSS Tricks
26pt	35px	2.2em	220%		CSS Tricks
27pt	36px	2.25em	225%		CSS Tricks
28pt	37px	2.3em	230%		CSS Tricks
29pt	38px	2.35em	235%		CSS Tricks
30pt	40px	2.45em	245%		CSS Tricks
32pt	42px	2.55em	255%		CSS Tricks
34pt	45px	2.75em	275%		CSS Tricks
36pt	48px	3em	300%		CSS Tricks

There is a good online PX to EM conversion calculator available. You can also use this calculator.