CSS units·25px
25px =
1.5625rem
18.75pt

25 px in rem — 1.5625 rem, 18.75 pt

25 px is 1.5625 rem and 18.75 pt — 0.26042 inches, 6.615 mm, and 156.25% of the root font size.

rem (root 16 px)
1.5625rem
pt (points)
18.75pt
pc (picas)
1.5625pc
percent of root
156.25%
inches
0.26042in
millimetres
6.615mm
centimetres
0.6615cm

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)
22px1.375rem16.5pt
23px1.4375rem17.25pt
24px1.5rem18pt
25px1.5625rem18.75pt
26px1.625rem19.5pt
27px1.6875rem20.25pt
28px1.75rem21pt

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 25 px?

1.5625 rem — that is 25 divided by 16.

Q. How many points is 25 px?

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

Q. What length is that?

0.26042 inches, or 6.615 mm — though a ruler on the screen will not agree.

Q. And as a percentage?

156.25% of the root font size.