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Convert Millimeters to Inches

Millimeters to Inches conversion table

Millimeters (mm)Inches (in)
1 mm0.03937 in
2 mm0.07874 in
5 mm0.19685 in
10 mm0.393701 in
25 mm0.984252 in
50 mm1.968504 in
100 mm3.937008 in
200 mm7.874016 in
500 mm19.685039 in
1000 mm39.370079 in

How to convert millimeters to inches

Millimeters offer precise metric measurements for engineering, machining, and rainfall, while inches serve similar roles in imperial contexts. One inch equals exactly 25.4 millimeters, making the conversion straightforward but producing small decimal values in the inch direction.

Convert millimeters to inches by dividing by 25.4. Formula: inches = mm ÷ 25.4. A 10 mm bolt diameter equals 10 ÷ 25.4 = 0.394 inches (just under 3/8 inch). Sheet metal at 1.5 mm thick is 0.059 inches.

3D printing, PCB design, and firearms specifications often list tolerances in millimeters for metric audiences and inches for American markets. A 0.5 mm pencil lead is 0.020 inches wide.

Common equivalents: 25.4 mm = 1 inch, 10 mm ≈ 0.39 inch, 50 mm = 1.97 inches (about 2 inches), and 254 mm = 10 inches.

Related conversions

Inches to Millimeters

Frequently asked questions

25 mm ÷ 25.4 = 0.984 inches, essentially 1 inch.

Divide mm by 25.4 to get decimal inches, then convert to the nearest fraction (e.g., 0.125 = 1/8 inch). Machinists often use conversion charts for standard fractions.

1 mm = 1/25.4 ≈ 0.03937 inches, or roughly 1/25 of an inch.