= Mathmatives

Millimeters to Inches Converter (mm to inch)

Enter a value in millimeters to see it in inches instantly, or type in the inches box to convert the other way. 1 millimeter = 0.039370079 inches, and 1 inch = 25.4 millimeters.

Divide millimeters by 25.4. 10 mm is 0.3937 in (about 3/8 in), 25 mm is 0.984 in (just under 1 in) and 100 mm is 3.937 in. Common fractions: 1/16 in = 1.5875 mm, 1/8 in = 3.175 mm, 1/4 in = 6.35 mm, 1/2 in = 12.7 mm.

1 millimeter = 0.039370079 inches. Formula: in = mm × 0.039370079 (or mm ÷ 25.4)

1 millimeter in all length units
Centimeters (cm)0.1
Meters (m)0.001
Kilometers (km)0.000001
Inches (in)0.039370079
Feet (ft)0.0032808399
Yards (yd)0.0010936133
Miles (mi)0.0000006214
Nautical miles (nmi)0.00000054
Gaj (gaj)0.0010936133

How to convert millimeters to inches

in = mm × 0.039370079

Multiply the number of millimeters by 0.039370079. To convert inches back to millimeters, multiply by 25.4, or divide by 0.039370079.

Example: 5 millimeters × 0.039370079 = 0.19685039 inches.

Millimeters to Inches conversion table

MillimetersInches
1 mm0.039370079 in
2 mm0.078740157 in
3 mm0.11811024 in
4 mm0.15748031 in
5 mm0.19685039 in
6 mm0.23622047 in
7 mm0.27559055 in
8 mm0.31496063 in
9 mm0.35433071 in
10 mm0.39370079 in
12 mm0.47244094 in
15 mm0.59055118 in
20 mm0.78740157 in
25 mm0.98425197 in
30 mm1.1811024 in
40 mm1.5748031 in
50 mm1.9685039 in
60 mm2.3622047 in
70 mm2.7559055 in
75 mm2.9527559 in
80 mm3.1496063 in
90 mm3.5433071 in
100 mm3.9370079 in
200 mm7.8740157 in
250 mm9.8425197 in
500 mm19.685039 in
1,000 mm39.370079 in
InchesMillimeters
1 in25.4 mm
2 in50.8 mm
3 in76.2 mm
4 in101.6 mm
5 in127 mm
6 in152.4 mm
7 in177.8 mm
8 in203.2 mm
9 in228.6 mm
10 in254 mm
12 in304.8 mm
15 in381 mm
20 in508 mm
25 in635 mm
30 in762 mm
40 in1,016 mm
50 in1,270 mm
60 in1,524 mm
70 in1,778 mm
75 in1,905 mm
80 in2,032 mm
90 in2,286 mm
100 in2,540 mm
200 in5,080 mm
250 in6,350 mm
500 in12,700 mm
1,000 in25,400 mm

About the millimeter and the inch

The millimeter (millimetre) is one thousandth of a meter. It is the working unit on engineering drawings, screw and bolt sizes, paper sizes, phone dimensions and rainfall reports.

The inch is exactly 25.4 mm. It survives in screen sizes, tyre and wheel sizes, pipe diameters and paper sizes even in metric countries.

Frequently asked questions

How many inches are in a millimeter?

There are 0.039370079 inches in 1 millimeter. For any number of millimeters, multiply by 0.039370079.

How many millimeters are in a inch?

1 inch = 25.4 millimeters. To convert inches to millimeters, multiply by 25.4 or divide by 0.039370079.

What is 5 millimeters in inches?

5 millimeters = 0.19685039 inches (5 × 0.039370079).

Is the mm to inch conversion exact?

Yes. The 1959 international yard and pound agreement defined the yard as exactly 0.9144 meters, which makes the inch exactly 25.4 mm, the foot exactly 0.3048 m and the mile exactly 1,609.344 m. Every factor on this page follows from those definitions, so it is exact rather than approximate. Results are rounded to eight significant digits for display.

Related calculators

Last updated . Formulas are shown on the page and checked against the worked example.

Conversion factors are exact international definitions where one exists and standard reference values elsewhere. Results are rounded to 8 significant digits.