MM to Inches — Convert Millimeters to Inches

Convert millimeters to inches instantly, with a quick reference table. Free, in your browser — no sign-up.

✓Free
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How to

1Enter the value in millimeters.
2Read the result in inches.
3Use the table for common values, or ⇄ to reverse.

How to convert millimeters to inches

Divide the length in millimeters by 25.4, because one inch is exactly 25.4 mm. For example, 100 mm ÷ 25.4 = 3.94 inches. Millimeters give fine precision, which is why this conversion shows up in technical work.

Where you will use it

Millimeters-to-inches is an engineering and DIY staple: screw and bolt sizes, material thickness, 3D-printing dimensions, tool specs, and hardware sold in one system but used with tools in the other.

millimeters to inches conversion table

Quick reference for common values. 1 mm = 0.03937 in.

millimeters (mm)	inches (in)
1 mm	0.03937 in
2 mm	0.07874 in
3 mm	0.11811 in
4 mm	0.15748 in
5 mm	0.19685 in
10 mm	0.393701 in
15 mm	0.590551 in
20 mm	0.787402 in
25 mm	0.984252 in
50 mm	1.968504 in
75 mm	2.952756 in
100 mm	3.937008 in

FAQ

How many mm is 1 inch?+

1 inch is exactly 25.4 mm. To convert millimeters to inches, divide by 25.4.

What is 10 mm in inches?+

10 mm = 0.3937 inches. Divide any millimeter value by 25.4.

Is it free?+

Yes, completely free — no sign-up and no watermark.

Is my data private?+

Yes — this tool runs entirely in your browser. Your files and text are never uploaded.

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