CSS units·91px
91px =
5.6875rem
68.25pt

91 px in rem — 5.6875 rem, 68.25 pt

91 px is 5.6875 rem and 68.25 pt — 0.94792 inches, 24.077 mm, and 568.75% of the root font size.

rem (root 16 px)
5.6875rem
pt (points)
68.25pt
pc (picas)
5.6875pc
percent of root
568.75%
inches
0.94792in
millimetres
24.077mm
centimetres
2.4077cm

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)
88px5.5rem66pt
89px5.5625rem66.75pt
90px5.625rem67.5pt
91px5.6875rem68.25pt
92px5.75rem69pt
93px5.8125rem69.75pt
94px5.875rem70.5pt

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 91 px?

5.6875 rem — that is 91 divided by 16.

Q. How many points is 91 px?

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

Q. What length is that?

0.94792 inches, or 24.077 mm — though a ruler on the screen will not agree.

Q. And as a percentage?

568.75% of the root font size.