Convert mm to inches

Millimeters to inches. Enter a value to convert, or use the mm to inches chart further down the page.

1 mm = 0.03937007874 in

1 millimeter equals 0.03937007874 inches. Going the other way, 1 inch = 25.4 millimeters.

From

Check this before you rely on it. This converter is provided free and without warranty, and its results are not professional advice.

How to convert mm to inches

To convert millimeters to inches, multiply the millimeter value by 0.03937007874. You can also divide by 25.4 to get the same answer.

in = mm × 0.03937007874

Worked example

Convert 15 mm to inches:

15 mm = 0.5905511811 in

15 mm in other forms

Form	Value	Note
Nearest 1/16 inch	9/16″	≈ 0.5625 in
Nearest 1/32 inch	19/32″	≈ 0.59375 in

mm to inches conversion chart

Use this mm to inches table for quick reference without typing anything.

mm to inches conversion table
millimeters (mm)	inches (in)	Nearest 1/16″
0.01 mm	0.0003937007874 in	0″
0.1 mm	0.003937007874 in	0″
1 mm	0.03937007874 in	1/16″
2 mm	0.07874015748 in	1/16″
3 mm	0.1181102362 in	1/8″
5 mm	0.1968503937 in	3/16″
10 mm	0.3937007874 in	3/8″
20 mm	0.7874015748 in	13/16″
50 mm	1.968503937 in	1 15/16″
100 mm	3.937007874 in	3 15/16″
1,000 mm	39.37007874 in	39 3/8″

Common mm to inches values

Ready-made answers for the mm to inches conversions people look up most often.

1 mm 1.5 mm 2 mm 2.5 mm 3 mm 4 mm 5 mm 6 mm 7 mm 8 mm 9 mm 10 mm 12 mm 12.7 mm 15 mm 16 mm 18 mm 20 mm 22 mm 25 mm 25.4 mm 30 mm 32 mm 40 mm 50 mm 60 mm 70 mm 75 mm 80 mm 100 mm 150 mm 200 mm

What is a millimeter?

The millimeter is a metric unit equal to one thousandth of a meter. It is the smallest unit marked on a standard metric ruler and is the working unit of engineering drawings, machining tolerances and rainfall measurement.

What is an inch?

The inch has been defined as exactly 25.4 millimeters since the 1959 international yard and pound agreement. It is the base unit of the imperial and US customary length system and is still standard for screen sizes, pipe diameters and construction in the United States.

Frequently asked questions

How many millimeters are in an inch?

There are exactly 25.4 millimeters in one inch. This is not an approximation — the inch has been legally defined as exactly 25.4 mm since the 1959 international yard and pound agreement.

What is 10 mm in inches?

10 mm equals 0.3937007874 inches, which is just under 25/64 of an inch. For practical work it is usually rounded to 0.394 inches, or the nearest 1/64 inch marking.

Is 25 mm the same as 1 inch?

Not quite. One inch is 25.4 mm, so 25 mm is slightly smaller — about 0.984 inches. The 0.4 mm difference matters for machining and fastener sizing, though it is negligible for rough measurement.

Related length conversions

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