CSS Unit Converter
px ↔ rem ↔ em ↔ pt, by root size.
Runs entirely in your browser — nothing you enter is uploaded, logged, or tracked.
Convert between px, rem, em, pt, and percent against your chosen root font size — the math behind every responsive type scale, done instantly.
px
— rem
— em
— pt
— Frequently asked questions
How do px and rem relate?
rem is relative to the root font size (16px by default), so 1rem = 16px, 24px = 1.5rem. Change the base size and every conversion updates.
Why convert px to rem?
Sizing in rem lets your whole layout scale with the user’s browser font-size preference — better for accessibility than fixed pixels.