Looking for a quick way to mm to inch convert without memorizing formulas? This page explains how to convert millimeter and inches in seconds, with clear examples, a handy reference table, and FAQs. Use the mm inches conversion calculator above to get instant results and a fraction reading for practical work.
MM to Inch Converter
Convert millimeters ⟷ inches instantly — centered approx answers
Millimeters ⟷ Inches
Millimeters (mm)
Inches (in)
Other Converted Values
How to convert mm to inch
- Core formula: inches = millimeters ÷ 25.4
- Why 25.4? By definition, 1 inch equals exactly 25.4 millimeters.
Examples:
- 100 mm in inches = 100 ÷ 25.4 = 3.9370″
- 150 mm to inch = 150 ÷ 25.4 = 5.9055″
- 3 mm to inch = 3 ÷ 25.4 = 0.1181″
Tip: For woodworking or hardware, use the fraction output (nearest 1/64″) for tape-measure accuracy.
Quick mm to Inches reference table (common values)
| Millimeters (mm) | Inches (in) |
|---|---|
| 10 mm | 0.3937″ |
| 25.4 mm | 1″ |
| 50 mm | 1.9685″ |
| 75 mm | 2.9528″ |
| 100 mm | 3.9370″ |
| 150 mm | 5.9055″ |
| 200 mm | 7.8740″ |
| 300 mm | 11.8110″ |
| 500 mm | 19.6850″ |
| 600 mm | 23.6220″ |
| 700 mm | 27.5591″ |
| 900 mm | 35.4331″ |
Use the calculator for any custom value—these are just starting points.
Common mm to inches conversions users search
- 200 mm in inch = 7.8740″
- 500 mm in inch = 19.6850″
- 600 mm in inch = 23.6220″
- 700 mm in inch = 27.5591″
- 900 mm in inch = 35.4331″
- 100 mm to inch = 3.9370″
- 10 mm in inch = 0.3937″
Reverse: convert inch to mm
Need inches to mm instead? Multiply by 25.4.
- mm = inches × 25.4
- mm in 12 inch = 12 × 25.4 = 304.8 mm
- mm in 3 inch = 3 × 25.4 = 76.2 mm
- mm in 4 inch = 4 × 25.4 = 101.6 mm
- mm in 2 inch = 2 × 25.4 = 50.8 mm
Fraction vs decimal: when to use which
- Decimal inches (e.g., 3.9370″) are perfect for CAD, CNC, and specifications.
- Fraction inches (e.g., 3 15/16″) are better on the job site or when reading a tape.
The calculator shows both to remove guesswork.
FAQ: millimeter and inches
1 inch = 25.4 mm (exact). This is the international standard definition.
Use the formula: inches = millimeters ÷ 25.4. Example: 32 mm ÷ 25.4 = 1.2598″.
Multiply by 25.4. Example: 2″ × 25.4 = 50.8 mm.
3 inches = 76.2 mm.
4 inches = 101.6 mm.
12 inches = 304.8 mm.
3 mm = 0.1181″.
Yes. Since 1959, 1 inch has been defined internationally as exactly 25.4 millimeters.
Use decimal inches for CAD/CNC/engineering specs (e.g., 3.9370″). Use fractional inches for tape measures and on‑site work (e.g., ≈ 3 15/16″).
The fraction is an approximation to the nearest 1/64″. It’s designed for practical measuring, so tiny differences from the exact decimal are normal and expected.
Enter the value in the calculator, copy the decimal inch for specifications, and use the fraction line for physical measuring. This gives both precision and practicality.
Why this converter?
- Accurate mm in inches and inches to mm conversions
- Fraction readout for real-world measuring
- Clear layout for quick scanning and fewer mistakes
Bookmark this page for the next time you need to convert mm to inch fast.