CSS units·70px
70px =
4.375rem
52.5pt

70 px in rem — 4.375 rem, 52.5 pt

70 px is 4.375 rem and 52.5 pt — 0.72917 inches, 18.521 mm, and 437.5% of the root font size.

rem (root 16 px)
4.375rem
pt (points)
52.5pt
pc (picas)
4.375pc
percent of root
437.5%
inches
0.72917in
millimetres
18.521mm
centimetres
1.8521cm

Why rem divides by 16

Because browsers default the root font size to 16 px, and rem is a multiple of it. When a reader enlarges text in their browser settings, only the parts written in rem grow — anything pinned in px stays put.

Nearby sizes

pxrem (root 16 px)pt (points)
67px4.1875rem50.25pt
68px4.25rem51pt
69px4.3125rem51.75pt
70px4.375rem52.5pt
71px4.4375rem53.25pt
72px4.5rem54pt
73px4.5625rem54.75pt

On screen, pt and inches are still pixels

CSS fixes one inch at 96 px and one point at 1/72 inch. So 16 px is exactly 12 pt — but hold a ruler to the screen and that "inch" will not measure an inch.

Sizes you meet most

Body text at 16, small text at 14, spacing at 8, 24 and 32 — the values that keep coming back.

How to read this

  • rem = px ÷ 16, because browsers default the root font size to 16 px.
  • pt = px × 0.75, since CSS fixes an inch at 96 px and a point at 1/72 inch.
  • One pc is 12 pt, and one inch is both 96 px and 72 pt.
  • Use rem for text and spacing; keep px for hairlines such as borders.

Frequently asked questions

Q. How many rem is 70 px?

4.375 rem — that is 70 divided by 16.

Q. How many points is 70 px?

52.5 pt. A point is 1/72 inch and an inch is 96 px, so you multiply by 0.75.

Q. What length is that?

0.72917 inches, or 18.521 mm — though a ruler on the screen will not agree.

Q. And as a percentage?

437.5% of the root font size.