How do you convert inch to millimeter?
To convert inches to millimeters, multiply the value by the conversion factor 25.4. In this tool, 1 inch equals 25.4 millimeter.
Convert inches to mm
Convert inches (in) to millimeters (mm) instantly with accurate results, reverse conversion, and a quick reference table.
Inch to Millimeter formula
Main formula: 1 inch = 25.4 millimeter
Reverse formula: 1 millimeter = 0.03937007874 inch
Use the swap button to move between both directions without retyping the number.
Inch
Definition: An inch (symbol: in) is a unit of length in the imperial and US customary systems equal to 1/12 of a foot.
History/origin: The inch has long been used in English measurement systems and was standardized internationally at 25.4 millimeters.
Current use: Inches are often used for screens, pipe sizes, product dimensions, and small construction measurements.
Millimeter
Definition: A millimeter (symbol: mm) is a metric unit of length equal to one-thousandth of a meter.
History/origin: The millimeter comes from the metric system, where the prefix "milli" means one-thousandth.
Current use: Millimeters are commonly used for small engineering tolerances, paper thickness, wiring sizes, and precise product dimensions.
Inch to Millimeter conversion table
| Inch [in] | Millimeter [mm] |
|---|---|
| 0.01 in | 0.254 mm |
| 0.1 in | 2.54 mm |
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 25 in | 635 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
| 1,000 in | 25,400 mm |
Convert inches to mm FAQs
What is 1 inch in millimeters?
1 inch is equal to 25.4 millimeters. This page updates the result instantly when you type a number into the converter box.
What is the reverse conversion from millimeter to inch?
The reverse conversion is also available. 1 millimeter equals 0.03937007874 inches, and you can use the swap arrows to flip the calculator instantly.
Can this inches to mm converter handle decimals and negative values?
Yes. The calculator accepts whole numbers, decimals, and negative values. It also checks for invalid text input and shows a validation message if the entry is not a valid number.
Is this inches to mm converter free to use?
Yes. This online converter is free to use and works in the browser. You can convert, clear the fields, and use the swap button without installing anything.