Millimeters to Inches

Type a value in mm and get in instantly: 1 mm = 0.0394 in

Millimeters (mm)

Inches (in) 0.0394

1 mm = 0.0394 in

in = mm × 0.0393701Formula

mm = in × 25.4Reverse formula

1 mm = 0.0393701 inFactor

The conversion between millimeters (mm) and inches (in) is fixed: 1 mm = 0.0394 in and 1 in = 25.4 mm. To convert mm to in, multiply by 0.0394; to go the other way, multiply by 25.4 (or divide by 0.0394). For example, 10 mm = 0.3937 in and 100 mm = 3.937 in.

Enter any value in the converter above; the result updates as you type. You will also find a ready-made table for common values, the formula, and a link to the reverse conversion (inches to millimeters).

One inch is exactly 25.4 mm. Drill bits, bolts and pipes are often sized in fractions of an inch: 1/4 in = 6.35 mm, 1/2 in = 12.7 mm, 3/4 in = 19.05 mm.

Quick answers

1 mm = 0.0394 in 4 mm = 0.1575 in 10 mm = 0.3937 in 20 mm = 0.7874 in 40 mm = 1.5748 in 75 mm = 2.9528 in 250 mm = 9.8425 in 1,000 mm = 39.37 in

Millimeters to Inches conversion table

Millimeters (mm)	Inches (in)
1 mm	0.0394 in
2 mm	0.0787 in
3 mm	0.1181 in
4 mm	0.1575 in
5 mm	0.1969 in
6 mm	0.2362 in
8 mm	0.315 in
10 mm	0.3937 in
12 mm	0.4724 in
15 mm	0.5906 in
20 mm	0.7874 in
25 mm	0.9843 in
30 mm	1.1811 in
40 mm	1.5748 in
50 mm	1.9685 in
60 mm	2.3622 in
75 mm	2.9528 in
100 mm	3.937 in
150 mm	5.9055 in
200 mm	7.874 in
250 mm	9.8425 in
300 mm	11.811 in
500 mm	19.685 in
1,000 mm	39.37 in

Inches to Millimeters quick table

Inches (in)	Millimeters (mm)
0.125 in	3.175 mm
0.375 in	9.525 mm
0.625 in	15.875 mm
1 in	25.4 mm
2 in	50.8 mm
4 in	101.6 mm
6 in	152.4 mm
10 in	254 mm
18 in	457.2 mm
36 in	914.4 mm

Frequently Asked Questions

How many inches are in 1 Millimeter?

1 mm = 0.0394 in. Multiply a value in mm by 0.0394 to get in.

How do I convert inches to millimeters?

Multiply the value in in by 25.4, or divide it by 0.0394. For example, 0.3937 in ≈ 10 mm.

What is 100 mm in in?

100 mm = 3.937 in.

Is the factor 0.0394 exact?

Both units have exact international definitions, so the factor is fixed; only the displayed value is rounded.

Open the unit converter 13 categories, both directions; Millimeter ↔ Inch preselected

More length conversions

Centimeter → Inch 1 cm = 0.3937 in Inch → Centimeter 1 in = 2.54 cm Meter → Foot 1 m = 3.2808 ft Foot → Meter 1 ft = 0.3048 m Kilometer → Mile 1 km = 0.6214 mi Mile → Kilometer 1 mi = 1.6093 km Foot → Centimeter 1 ft = 30.48 cm Centimeter → Foot 1 cm = 0.0328 ft Yard → Meter 1 yd = 0.9144 m Meter → Yard 1 m = 1.0936 yd Inch → Foot 1 in = 0.0833 ft Foot → Inch 1 ft = 12 in Nautical mile → Kilometer 1 nmi = 1.852 km Kilometer → Nautical mile 1 km = 0.54 nmi