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Inches to Millimeters Converter
Convert inches to millimeters by typing a value: the answer appears as you type. One in equals 25.4 mm, so to go from inches to millimeters you multiply by 25.4. A table of common values is included below.
- The same number of millimeters in inches
- 0.3937 in
Inches to millimeters table
| Inches (in) | Millimeters (mm) |
|---|
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Formula
How to use it
- Type the number of inches.
- Read the result in millimeters.
- Open the table for common values, or use the reverse converter to go from millimeters to inches.
Worked examples
1 in in millimeters
- Millimeters
- 25.4 mm
15 in in millimeters
- Millimeters
- 381 mm
Quick reference
1 in = 25.4 mm. 2 in = 50.8 mm. 3 in = 76.2 mm. 4 in = 101.6 mm. 5 in = 127 mm. 10 in = 254 mm. 15 in = 381 mm. 20 in = 508 mm.
Good to know
The inch is defined as exactly 2.54 centimeters, and the foot as exactly 0.3048 meters, so conversions between metric and US customary lengths are exact rather than approximate.
Questions people ask
How many millimeters are in 1 in?
1 in is 25.4 mm.
How do I convert inches to millimeters?
Multiply by 25.4. For example, 5 in × 25.4 = 127 mm.
What is 100 in in millimeters?
100 in is 2,540 mm.