Inch (in) to Millimeter (mm)
1 in = 25.4 mm · Free instant converter, no signup required.
Direct Answer
1 in = 25.4 mm
Formula: mm = in × 25.4. This page supports instant conversion, reference table checks, and related unit links.
About this conversion
This Koverts page converts Inch (in) to Millimeter (mm) under Length Converter. Fixed ratio: 1 in = 25.4 mm; inverse: 1 mm = 0.03937 in. Length units follow the international inch (25.4 mm) and derived feet, yards, and miles—the same factors power the headline, formula box, reference table, and FAQ.
Inch (in) and Millimeter (mm) are units used in Length Converter. Enter a value above to convert Inch (in) into Millimeter (mm) using the standard relationship for this category.
Millimeter (mm) is the target unit on this page. Results come from Inch (in) using the same rules as the calculator and the reference table below.
Typical uses
- Compare Inch (in) and Millimeter (mm) for everyday estimates and planning
- Use with homework, DIY projects, and hobby measurements
- Read international labels, manuals, and product specs with less guesswork
- Educational reference only — verify medical, legal, or engineering use with authoritative sources
Common reference values
- 1 in = 25.4 mm
- 10 in = 254 mm
- 100 in = 2,540 mm
Tip: 1 in equals 25.4 mm. Multiply your amount by 25.4 to convert from in to mm.
Did you know? Koverts keeps conversion math transparent: you see the factor, the table, and the same rules everywhere on the page.
Educational reference — always verify critical measurements (medical, engineering, legal) with primary sources.
// inch Conversion table millimeter
| Inch (in) (in) | Millimeter (mm) (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
| 250 in | 6,350 mm |
| 500 in | 12,700 mm |
| 1000 in | 25,400 mm |
How to convert
Inch (in) → Millimeter (mm)
To convert from Inch (in) (in) to Millimeter (mm) (mm)，multiply your value by 25.4.
For example，10 in = 254 mm.
// Frequently Asked Questions
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