inches to mm converter

1 in = 25.4 mm (exact); 1 mm = 0.0393701 in. To convert inches to mm, multiply by 25.4.

Conversion formula

mm = in × 25.4

Conversion table

1 in25.4 mm
2 in50.8 mm
3 in76.2 mm
4 in101.6 mm
5 in127 mm
6 in152.4 mm
7 in177.8 mm
8 in203.2 mm
9 in228.6 mm
10 in254 mm
15 in381 mm
20 in508 mm
25 in635 mm
50 in1270 mm
100 in2540 mm
1000 in25400 mm

Reverse conversion table

1 mm0.0393701 in
2 mm0.0787402 in
3 mm0.11811 in
4 mm0.15748 in
5 mm0.19685 in
6 mm0.23622 in
7 mm0.275591 in
8 mm0.314961 in
9 mm0.354331 in
10 mm0.393701 in
15 mm0.590551 in
20 mm0.787402 in
25 mm0.984252 in
50 mm1.9685 in
100 mm3.93701 in
1000 mm39.3701 in

Key facts

1 inch25.4 mm (exact)
1 millimetre0.0393701 in
Formulamm = in × 25.4
0.5 in12.7 mm

Frequently asked questions

How many mm is 1 inch?

1 inch equals exactly 25.4 mm. Multiply the inch value by 25.4.

How do I convert inches to mm?

Multiply the inch value by 25.4. For example, 2 in × 25.4 = 50.8 mm.

Reverse conversion

Printable A4 conversion cheat sheet — see the Downloads page

Related conversions