mm to inches Converter
Unit Converter
Instant · Precise · Universal
32 units available
6 categories total
How to Convert Millimeter to Inch
To convert mm to inches: divide by 25.4. To convert inches to mm: multiply by 25.4.
1 mm = 0.001 m = 0.1 cm = 1,000 µm. There are 25.4 mm in one inch.
For example, 1 Millimeter (mm) = 0.03937007874 Inch (in).
Millimeter to Inch — Common Values
| Millimeter (mm) | Inch (in) |
|---|---|
| 0.1 | 0.003937007874 |
| 0.5 | 0.01968503937 |
| 1 | 0.03937007874 |
| 2 | 0.07874015748 |
| 5 | 0.1968503937 |
| 10 | 0.3937007874 |
| 25 | 0.9842519685 |
| 50 | 1.968503937 |
| 100 | 3.937007874 |
| 500 | 19.68503937 |
| 1000 | 39.37007874 |
About Millimeter (mm)
Definition
The millimeter is a unit of length equal to one thousandth of a meter (10⁻³ m), or one tenth of a centimeter.
Mathematical Relationship
1 mm = 0.001 m = 0.1 cm = 1,000 µm. There are 25.4 mm in one inch.
Conversion Formula
To convert mm to inches: divide by 25.4. To convert inches to mm: multiply by 25.4.
Practical Applications
Engineering drawings, screw thread specifications, rainfall measurements, paper thickness, and small component dimensions.
Interesting Facts
Standard A4 paper is 210 × 297 mm. A credit card is about 0.76 mm thick.
Common Mistakes
Confusing mm with cm on rulers — each cm mark has 10 mm divisions. Also, misreading calipers by one mm.
Educational Tips
A dime is about 1.3 mm thick — use it as a quick visual reference for millimeter scale.
About Inch (in)
Definition
The inch is a unit of length in the imperial and US customary systems, defined as exactly 25.4 millimeters.
Mathematical Relationship
1 in = 25.4 mm = 2.54 cm = 1/12 ft = 1/36 yd.
Conversion Formula
To convert inches to cm: multiply by 2.54. To convert cm to inches: divide by 2.54.
Practical Applications
Screen sizes (TVs, monitors), drill bit sizes, pipe diameters, screw dimensions, and rainfall measurement in the US.
Interesting Facts
King Edward II of England defined the inch as 'three grains of barley, dry and round, placed end to end' in 1324.
Common Mistakes
Forgetting that fractions of an inch use powers of 2 (1/2, 1/4, 1/8, 1/16), not decimal subdivisions like metric.
Educational Tips
Your thumb from tip to first knuckle is roughly 1 inch — a handy (literal) reference.