Convert inches to mm
Enter the value to convert from inch to millimeter.
How to Convert Inch to Millimeter
Converting inch to millimeter is straightforward using our conversion calculator.
Conversion Formula
mm = in × 25.4Reverse conversion: Convert mm to inches
Comparison: Inch vs Millimeter
When to Use Each Unit
Inch: Primary length unit in the United States for construction, manufacturing, and everyday measurements.
Millimeter: Standard in engineering, manufacturing, medicine, and any field requiring precise measurements. Used for tolerances and small components.
Common Conversion Values
- 1 in = 2.54 cm
- 1 in = 25.4 mm
- 12 in = 1 ft
- 1 in ≈ 0.0254 m
About Inch
Definition: The inch (symbol: in) is an imperial unit of length equal to 1/12 of a foot, approximately 2.54 centimeters.
History: Originally based on the width of a human thumb. Standardized in 1959 as exactly 25.4 millimeters internationally.
Current Use: Primary length unit in the United States for construction, manufacturing, and everyday measurements.
Examples: Screen sizes: 15-32 inches, screw sizes: 1/4-1 inch, lumber: 2×4 inches, pipe diameters: 1/2-12 inches
About Millimeter
Definition: The millimeter (symbol: mm) is a unit of length equal to one thousandth of a meter. Used for precise measurements and small dimensions.
History: Developed alongside the metric system for measurements requiring higher precision than centimeters could provide.
Current Use: Standard in engineering, manufacturing, medicine, and any field requiring precise measurements. Used for tolerances and small components.
Examples: Paper thickness: 0.1mm, coin thickness: 1-3mm, drill bits: 1-20mm, rainfall: measured in mm