CSS units·133px
133px =
8.3125rem
99.75pt

133 px in rem — 8.3125 rem, 99.75 pt

133 px is 8.3125 rem and 99.75 pt — 1.38542 inches, 35.19 mm, and 831.25% of the root font size.

rem (root 16 px)
8.3125rem
pt (points)
99.75pt
pc (picas)
8.3125pc
percent of root
831.25%
inches
1.38542in
millimetres
35.19mm
centimetres
3.519cm

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)
130px8.125rem97.5pt
131px8.1875rem98.25pt
132px8.25rem99pt
133px8.3125rem99.75pt
134px8.375rem100.5pt
135px8.4375rem101.25pt
136px8.5rem102pt

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 133 px?

8.3125 rem — that is 133 divided by 16.

Q. How many points is 133 px?

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

Q. What length is that?

1.38542 inches, or 35.19 mm — though a ruler on the screen will not agree.

Q. And as a percentage?

831.25% of the root font size.