HTML CSS Font Size Comparisons & Conversions

Pixels	Ems	Points	Percents
8px	0.5em	6pt	50%
9px	0.55em	7pt	55%
10px	0.625em	7.5pt	62.50%
11px	0.7em	8pt	70%
12px	0.75em	9pt	75%
13px	0.8em	10pt	80%
14px	0.875em	10.5pt	87.50%
15px	0.95em	11pt	95%
16px	1em	12pt	100%
17px	1.05em	13pt	105%
18px	1.125em	13.5pt	112.50%
19px	1.2em	14pt	120%
20px	1.25em	14.5pt	125%
21px	1.3em	15pt	130%
22px	1.4em	16pt	140%
23px	1.45em	17pt	145%
24px	1.5em	18pt	150%
26px	1.6em	20pt	160%
29px	1.8em	22pt	180%
32px	2em	24pt	200%
35px	2.2em	26pt	220%
36px	2.25em	27pt	225%
37px	2.3em	28pt	230%
38px	2.35em	29pt	235%
40px	2.45em	30pt	245%
42px	2.55em	32pt	255%
45px	2.75em	34pt	275%
48px	3em	36pt	300%

Pixels Are Relative to the Screen Resolution and Give the Designer the Greatest Control and Precision
Ems Are Relative to the Parent Element and the Most Accessible Option Because They Allow Browser Defaults to Modify Them
Percentages Are Relative to the Surrounding Text
Points Are Units of Measure Not Relative to A Screen and Should Only Be Used For Printing
Browser Defaults Are Usually 16px/1em