At One Place

Millimeters to inches

1 millimeter in inches
1 mm = 0.03937 in
in = mm × 0.03937007874

To convert millimeters to inches, multiply by 0.03937007874. The table below gives the values people look up most often, and the converter works for any number.

Millimeters to inches table

Common millimeter values converted to inches.
Millimeters Inches
1 mm 0.03937
2 mm 0.07874
3 mm 0.11811
4 mm 0.15748
5 mm 0.19685
10 mm 0.3937
15 mm 0.59055
20 mm 0.7874
25 mm 0.98425
30 mm 1.181102
40 mm 1.574803
50 mm 1.968504
75 mm 2.952756
100 mm 3.937008
250 mm 9.84252
500 mm 19.68504
1,000 mm 39.37008

How the conversion works

The relationship is in = mm × 0.03937007874. Both units measure length, so the conversion is a fixed factor that never changes. The figure is exact rather than approximate: since the international yard and pound agreement of 1959, an inch is defined as exactly 25.4 millimetres and a pound as exactly 0.45359237 kilograms, and every other imperial and US customary unit here is derived from those two.

Common questions

How many inches are in one millimeter?
One millimeter equals 0.03937 inches. in = mm × 0.03937007874.
How do you convert millimeters to inches?
Use in = mm × 0.03937007874. So 10 mm is 0.3937 in.
How many millimeters are in one inch?
One inch equals 25.4 millimeters, which is the reverse of the conversion above.

Related pages

Sources

  1. Guide for the Use of the International System of Units (SP 811) — NIST (Public domain (US Government))
  2. The International System of Units (SI Brochure) — Bureau International des Poids et Mesures
  3. Calculated on this page — At One Place

How these figures are compiled and checked