MM to Inches Converter
Convert millimeters to inches instantly, and inches back to mm. Based on the exact 1 in = 25.4 mm definition.
Independently verified for accuracy
Calculator by Toolsloft ↗- Result
- 0.03937 Inches (in)
- Conversion
- 1 Millimeters (mm) = 0.03937 Inches (in)
Convert millimeters to inches, and inches back to millimeters with the swap button. This is the one for drill bits, screw lengths, phone screens, and fine measurements given in mm when your tools are in inches. Type the number and read the result.
How this is calculated
One inch equals exactly 25.4 millimeters by international agreement, so millimeters are divided by 25.4 to get inches and inches are multiplied by 25.4 to get millimeters. Results are shown to six decimal places, which matters for small parts.
How to use
- Enter the number of millimeters.
- Keep the direction on mm to inches, or press Swap units for inches to mm.
- Read the result in inches.
Examples
- One inch check:
25.4 mm = 1 in - Bolt length:
100 mm = 3.937008 in - Inches to mm:
12 in = 304.8 mm
FAQ
- How do I convert mm to inches?
- Divide the number of millimeters by 25.4. For example, 100 mm divided by 25.4 is about 3.94 inches.
- How many millimeters are in an inch?
- Exactly 25.4 millimeters. That is the official definition of the inch, so the conversion is exact rather than an approximation.