Convert between px, em, rem, and % for CSS font sizes.
px
px
Quick reference
| px | rem (root 16) | em (parent 16) |
|---|---|---|
| 12px | 0.75rem | 0.75em |
| 16px | 1rem | 1em |
| 24px | 1.5rem | 1.5em |
FAQ
rem vs em?
rem is relative to root html element. em is relative to parent. Prefer rem for predictability.
Why use rem?
Users can resize text in browser settings — rem-based sizes scale accessibly.
Default root?
16px in all browsers by default.
Free?
Yes.