Inches to millimeters
Type a value in in to get it in mm instantly.
That's 1.27× as long as a door, while a giraffe is 2.2× longer. Walking, you would cover that in 1.814 seconds.
Convert the other way: mm to in
What it means
How long is that?
Reference lengths are typical values. The inch, foot, yard and mile are defined exactly in meters (1 inch = 2.54 cm).
The math
How to convert in to mm
To convert inches to millimeters, multiply by 25.4.
Example: 100 in × 25.4 = 2,540 mm.
In the other direction, 1 mm = 0.0393701 in.
Every unit
Your length in every unit
Tables
in to mm conversion table
| in | mm |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 30 in | 762 mm |
| 50 in | 1,270 mm |
| 75 in | 1,905 mm |
| 100 in | 2,540 mm |
| 150 in | 3,810 mm |
| 200 in | 5,080 mm |
| 500 in | 12,700 mm |
| 1,000 in | 25,400 mm |
mm to in conversion table
| mm | in |
|---|---|
| 1 mm | 0.0393701 in |
| 2 mm | 0.0787402 in |
| 3 mm | 0.11811 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 |
| 30 mm | 1.1811 in |
| 50 mm | 1.9685 in |
| 75 mm | 2.95276 in |
| 100 mm | 3.93701 in |
| 150 mm | 5.90551 in |
| 200 mm | 7.87402 in |
| 500 mm | 19.685 in |
| 1,000 mm | 39.3701 in |
Quick answers
Quick answers
- How many mm is 1 in?
- 1 in is 25.4 mm.
- How many mm is 10 in?
- 10 in is 254 mm.
- How many mm is 100 in?
- 100 in is 2,540 mm.
The units
About these units
Inches (in)
The inch is exactly 2.54 cm by international agreement since 1959. Screens, pipes, wheels and paper sizes in the US are all measured in inches.
Millimeters (mm)
A millimeter is a thousandth of a meter, roughly the thickness of a credit card. It is the everyday unit of engineering drawings and rainfall.
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