Unit Converter
Convert length, weight, temperature, and all physical units
How to Convert Millimeters to Inches
One inch is exactly 25.4 millimeters. This conversion is frequently used in precision manufacturing, hardware specifications, and 3D printing where parts may be specified in either millimeters or inches.
Conversion Formula
in = mm ÷ 25.4
Quick Reference Table
| Millimeter | Inch |
|---|---|
| 1 | 0.0394 |
| 5 | 0.1969 |
| 10 | 0.3937 |
| 25.4 | 1 |
| 50 | 1.9685 |
| 100 | 3.937 |
| 300 | 11.811 |
How to Use the Unit Converter
The Internet Octopus Unit Converter supports 14 categories and over 100 units. Enter a value and select units to see instant conversion results.
Supported Unit Categories
- Length — Millimeter, centimeter, meter, kilometer, inch, foot, yard, mile, nautical mile, and more
- Weight / Mass — Milligram, gram, kilogram, ton, pound, ounce, stone, grain, and more
- Volume — Milliliter, liter, gallon, quart, pint, cup, fluid ounce, tablespoon, teaspoon, and more
- Area — Square meter, square kilometer, acre, hectare, pyeong, and more
- Temperature — Convert between Celsius, Fahrenheit, and Kelvin
- Speed — Meter/second, kilometer/hour, mile/hour, knot, foot/second, and more
- Time — Millisecond, second, minute, hour, day, week, year, and more
- Digital Storage — Bit, byte, KB, MB, GB, TB, PB, and KiB, MiB, GiB, TiB, and more
- Pressure — Pascal, kilopascal, bar, atmosphere, PSI, mmHg, and more
- Energy — Joule, kilojoule, calorie, kilocalorie, watt-hour, kilowatt-hour, BTU, electronvolt, and more
- Power — Watt, kilowatt, megawatt, horsepower, and more
- Angle — Degree, radian, gradian, turn, and more
- Force — Newton, kilonewton, pound-force, kilogram-force, and more
- Frequency — Hertz, kilohertz, megahertz, gigahertz, and more
How to Use
- Enter a number in the left input field.
- Select the source unit from the left dropdown.
- Select the target unit from the right dropdown — only compatible units are shown.
- The result appears instantly. Use the swap button to reverse the conversion.