Converters
12
Inches to Millimeters Converter
Convert inches to millimeters instantly with the formula, worked examples, rounding guidance, and related distance conversions.
Units
85
Mode
Live
Pair-specific conversion guide
Inch to Millimeter formula
Use this Inch to Millimeter page for direct distance conversions. The calculator keeps the exact in to mm relationship on the page, so the result, formula, and examples all describe this specific pair.
Formula model
1 in = 25.4 mm
1 Inch equals
Quick factor: 1 in = 25.4 mm.
The current calculator value is 1 in, which equals 25.4 mm.
Use the conversion table to compare 1 in with the other units in the same category.
For heights and dimensions, keep extra decimals in mm and round only to the precision of the original in measurement.
Precision and rounding
The calculation uses the catalog's fixed conversion factors between in and mm. Full decimal precision is kept for the calculation; only the displayed value is rounded for readability.
Reference: NIST conversion factorsDistance
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Millimeters to Inches Converter
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Distance links
Conversion table
1 Inch equals
| Unit | Value |
|---|---|
| Meter m | 0.0254 |
| Kilometer km | 2.54E-05 |
| Centimeter cm | 2.54 |
| Millimeter mm | 25.4 |
| Foot ft | 0.0833333333333 |
| Yard yd | 0.0277777777778 |
| Mile mi | 1.57828282828E-05 |
| Nautical mile nmi | 1.37149028078E-05 |
FAQ
Inch to Millimeter questions
How do you convert Inch to Millimeter?
Use the formula 1 in = 25.4 mm. As a quick check, 1 in equals 25.4 mm.
Is the Inch to Millimeter conversion exact?
This page uses fixed constants from the Converter Science catalog. Displayed results are rounded only to keep the page readable.