CSS units·23px
23px =
1.4375rem
17.25pt

23 px in rem — 1.4375 rem, 17.25 pt

23 px is 1.4375 rem and 17.25 pt — 0.23958 inches, 6.085 mm, and 143.75% of the root font size.

rem (root 16 px)
1.4375rem
pt (points)
17.25pt
pc (picas)
1.4375pc
percent of root
143.75%
inches
0.23958in
millimetres
6.085mm
centimetres
0.6085cm

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)
20px1.25rem15pt
21px1.3125rem15.75pt
22px1.375rem16.5pt
23px1.4375rem17.25pt
24px1.5rem18pt
25px1.5625rem18.75pt
26px1.625rem19.5pt

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 23 px?

1.4375 rem — that is 23 divided by 16.

Q. How many points is 23 px?

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

Q. What length is that?

0.23958 inches, or 6.085 mm — though a ruler on the screen will not agree.

Q. And as a percentage?

143.75% of the root font size.