Convert between CSS units like pixels, ems, rems, percentages, and viewport units. Calculate responsive dimensions for web design.
Root (rem)
Parent (em)
Viewport W
Viewport H
Precision
100% of
Font for ch / ex measurement
1ch ≈ 0.5em · 1ex ≈ 0.5em1rem = 16px · 1em = 16px · 100vw = 1920px
Quick examples
px
Pixels
rem
Root em
em
Em
%
Percent
pt
Points
vw
Viewport width
vh
Viewport height
ch
Character
ex
x-height
cm
Centimetres
mm
Millimetres
in
Inches
pc
Picas
Tip: type into any field to convert live. Focus a field and press ↑ / ↓ to step (Shift = ×10, Alt = ×0.1).
