CSS 単位変換
無料のCSS単位変換ツール。ルートフォントサイズに基づいて、px、rem、em、pt、pc、物理単位間で変換します。レスポンシブデザインとCSSワークフローに。
Runs in your browserUpdated Apr 26, 2026
CSS units converter
rem
1rem
em
1em
pt
12pt
pc
1pc
in
0.1667in
cm
0.4233cm
よくある質問
›Is 1rem always 16px?
By default, yes — but if you change the root font-size, all rem values scale. We let you set the root for accurate conversion.
›rem vs em?
rem is relative to root font-size; em is relative to the parent's font-size. rem is more predictable for layout.
›Why use rem over px?
rem respects user font-size preferences (for accessibility) and scales the whole layout consistently.
›Is the converter free?
Yes — fully free, no signup.