Inch to Millimeter Converter
Free Length Converter - Meters to CM, Miles to Kilometers, Feet to Meters, Inches to CM - Convert M to CM Instantly
Inch
- Symbol
- in
- System
- Metric/Imperial
- Dimension
- Various
Millimeter
- Symbol
- mm
- System
- Metric/Imperial
- Dimension
- Various
Quick Reference Table
| Inch | Millimeter | Millimeter | Inch |
|---|---|---|---|
| 1 | 25.4 | 1 | 0.0393700787 |
| 2 | 50.8 | 2 | 0.0787401575 |
| 3 | 76.2 | 3 | 0.1181102362 |
| 5 | 127 | 5 | 0.1968503937 |
| 10 | 254 | 10 | 0.3937007874 |
| 25 | 635 | 25 | 0.9842519685 |
| 50 | 1270 | 50 | 1.968503937 |
| 100 | 2540 | 100 | 3.937007874 |
| 500 | 12700 | 500 | 19.6850393701 |
| 1000 | 25400 | 1000 | 39.3700787402 |
Conversion Formula
Millimeter = Inch × 25.4
Inch = Millimeter × 0.0393700787
Factors are from BIPM SI brochure and NIST SP 811, stored unrounded and computed via a base unit. Reverse factor is 1 ÷ 25.4.
How to convert Inch to Millimeter
Multiply the value in inch by 25.4 to get millimeter. For example, 5 Inch = 127 Millimeter. All results in the length & distance converter update instantly as you type, so you can see every unit at once without manual math.
Common mistakes
Do not round the factor to 25.4 too early — keep full precision until the final display. For length & distance, always verify critical calculations (medicine, engineering) with a second source.
FAQ
- How many Millimeter in 1 Inch?
- 1 Inch = 25.4 Millimeter.
- How many Inch in 1 Millimeter?
- 1 Millimeter = 0.0393700787 Inch.
- What is the source?
- BIPM/NIST via OmniConverter base-unit engine. Source table and formula above are exact.
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