What is the difference between rem and em?

rem is relative to the document root’s font size, em to the parent element’s. The same 1.5 becomes a different size depending on where it sits.

Because 16px is the default font size in most browsers. If you changed the root size, divide by that instead.

It is a print unit. On the web 1pt converts to about 1.333px.

CSS unit converter

Name: CSS 단위 변환
Author: KarmoLab

px · rem · em · pt · % · a table of common sizes

px·rem·em·pt·% 를 서로 바꿉니다. 루트 기준과 부모 기준을 나란히

루트 글자 크기 (html)

부모 글자 크기 (em 기준)

값

숫자

단위

px24

rem (루트 기준)1.5rem

em (부모 기준)1.5em

pt18pt

부모 대비 %150%

자주 쓰는 크기 — px → rem

10px0.625rem

12px0.75rem

14px0.875rem

16px1rem

18px1.125rem

20px1.25rem

24px1.5rem

28px1.75rem

32px2rem

40px2.5rem

48px3rem

64px4rem

rem 은 루트 기준, em 은 부모 기준입니다 — 같은 숫자라도 크기가 다릅니다.

Converts between px, rem, em, pt and percentages. Set the root font size and the parent font size separately to see rem and em next to each other.

What is the difference between rem and em?: rem is relative to the document root’s font size, em to the parent element’s. The same 1.5 becomes a different size depending on where it sits.
Why divide by 16?: Because 16px is the default font size in most browsers. If you changed the root size, divide by that instead.
When do I use pt?: It is a print unit. On the web 1pt converts to about 1.333px.

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