length conversion

How many millimeters are in 1 inch?

Quick answer, a live calculator, and reference values—built for fast, mobile-friendly lookups.

Main answer

1 inch = 25.4 millimeters

Amount (inches)

Result

1 inch = 25.4 millimeters

Factor: 25.4

There are 25.4 millimeters in 1 inch.

1 inch equals 25.4 millimeters. An inch is a common length unit for everyday sizing, crafts, and travel. A millimeter is another length unit you'll often see on rulers, road signs, and product dimensions.

Need the other direction?

Convert millimeters to inches.

Examples

1 inch
25.4 millimeters
5 inches
127 millimeters
10 inches
254 millimeters
100 inches
2,540 millimeters

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