CSS units·87px
87px =
5.4375rem
65.25pt

87 px in rem — 5.4375 rem, 65.25 pt

87 px is 5.4375 rem and 65.25 pt — 0.90625 inches, 23.019 mm, and 543.75% of the root font size.

rem (root 16 px)
5.4375rem
pt (points)
65.25pt
pc (picas)
5.4375pc
percent of root
543.75%
inches
0.90625in
millimetres
23.019mm
centimetres
2.3019cm

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)
84px5.25rem63pt
85px5.3125rem63.75pt
86px5.375rem64.5pt
87px5.4375rem65.25pt
88px5.5rem66pt
89px5.5625rem66.75pt
90px5.625rem67.5pt

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 87 px?

5.4375 rem — that is 87 divided by 16.

Q. How many points is 87 px?

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

Q. What length is that?

0.90625 inches, or 23.019 mm — though a ruler on the screen will not agree.

Q. And as a percentage?

543.75% of the root font size.