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Inches to Millimeters (in to mm)
1 inch = 25.4 mm. Type any number below, or pick a value from the chart.
Quick Reference
Formula
mm = in × 25.4
Example: 0.125 × 25.4 = 3.175
The other way round
1 millimeter = 0.0394 in
Inches to Millimeters (in to mm) chart
Tap a value for the worked answer.
More length conversions
About the Unit Converter
The unit converter changes values between metric and imperial units for length, weight, temperature, digital data, area, and volume.
How to use it
- 1 Choose a category, such as length or temperature.
- 2 Pick the unit to convert from and the unit to convert to.
- 3 Type a value to see the converted result straight away.
Frequently asked questions
How do I convert inches to millimeters?
Multiply by 25.4: there are 25.4 millimeters in one inch.
What is 1 inch in millimeters?
1 inch is 25.4 millimeters.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32. For example, 20 °C × 9/5 + 32 = 68 °F.
How many centimetres are in an inch?
One inch is exactly 2.54 centimetres, and one foot is 30.48 centimetres.
Is a kilobyte 1,000 or 1,024 bytes?
In SI units a kilobyte (kB) is 1,000 bytes. A kibibyte (KiB) is 1,024 bytes. Some operating systems still use "KB" to mean 1,024 bytes.