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Length conversion

Millimetre to Inch

One millimetre is 0.03937 inches. Enter any value below to convert it instantly, or use the reference table further down for the numbers you need most often.

1 mm = 0.03937 inInstantFree

Conversion rate

1 mm = 0.03937 in

in = mm × 0.03937

Result0.03937

1 mm = 0.03937 in

1 mm in every length unit
nm1,000,000
µm1,000
mm1
cm0.1
m0.001
km0.000001
in0.03937
ft0.0032808
yd0.0010936
mi6.2137e-7
nmi5.3996e-7
pt2.834646
pc0.23622
px3.779528

Reference

Millimetre to Inch table

The values people look up most often, rounded for practical use.

Millimetre (mm)Inch (in)
1 mm0.03937 in
2 mm0.07874 in
3 mm0.11811 in
5 mm0.19685 in
10 mm0.3937 in
15 mm0.59055 in
20 mm0.7874 in
25 mm0.98425 in
50 mm1.968504 in
100 mm3.937008 in
250 mm9.84252 in
500 mm19.68504 in
1,000 mm39.37008 in

How to convert millimetres to inches

Multiply the number of millimetres by 0.03937. That is the whole calculation: in = mm × 0.03937. To go back the other way, divide instead, or multiply by 25.4.

Worked example: 12 millimetres × 0.03937 = 0.47244 inches.

Where this conversion comes up

Length conversions show up constantly in printing, DIY, engineering drawings and anything bought from a country using the other measurement system. If you are converting in order to set a page or grid size, the graph paper generator accepts spacing in millimetres directly — and the on-screen ruler lets you check a printed result against both scales.

Quick answers

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Answers

Frequently asked questions

One millimetre equals 0.03937 inches. Going the other way, one inch is 25.4 millimetres.

Use in = mm × 0.03937. The converter above applies it for you, but the formula is useful in a spreadsheet — put your value in column A and the formula in column B.

The underlying factor is the exact internationally defined value. Results are rounded for readability, so very long decimals are trimmed — but the calculation itself carries full double precision.

Yes — press the ⇄ swap button in the converter, or use the dedicated Inch to Millimetre page.

No. The converter runs entirely in your browser, there is no account, and nothing you type is sent anywhere.

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