CSS units·17px
17px =
1.0625rem
12.75pt

17 px in rem — 1.0625 rem, 12.75 pt

17 px is 1.0625 rem and 12.75 pt — 0.17708 inches, 4.498 mm, and 106.25% of the root font size.

rem (root 16 px)
1.0625rem
pt (points)
12.75pt
pc (picas)
1.0625pc
percent of root
106.25%
inches
0.17708in
millimetres
4.498mm
centimetres
0.4498cm

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)
14px0.875rem10.5pt
15px0.9375rem11.25pt
16px1rem12pt
17px1.0625rem12.75pt
18px1.125rem13.5pt
19px1.1875rem14.25pt
20px1.25rem15pt

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 17 px?

1.0625 rem — that is 17 divided by 16.

Q. How many points is 17 px?

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

Q. What length is that?

0.17708 inches, or 4.498 mm — though a ruler on the screen will not agree.

Q. And as a percentage?

106.25% of the root font size.