Updated 2026 · By ToolFern

Inch to Millimeter Converter

Convert inches to millimeters (in to mm) instantly. Type a value and get the answer live, or use the table below. 1 in = 25.4 mm.

in
=
mm

How to convert inches to millimeters

To convert inches to millimeters, multiply the number of inches by 25.4. That is because 1 in = 25.4 mm. For example, 10 in = 254 mm.Enter any value in the box above and the answer updates instantly, no sign-up and nothing leaves your browser.

Inch to Millimeter conversion table

Inches (in)Millimeters (mm)
1 in25.4 mm
2 in50.8 mm
3 in76.2 mm
5 in127 mm
10 in254 mm
20 in508 mm
25 in635 mm
50 in1,270 mm
100 in2,540 mm
1,000 in25,400 mm

Frequently asked questions

How many millimeters in a inch?

1 in = 25.4 mm. So 1 inch equals 25.4 millimeters.

What is the in to mm formula?

Inches × 25.4 = Millimeters.

Does it work in reverse?

Yes. Use the Millimeter to Inch converter to go the other way.

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