Inches to mm Converter
Convert in to mm: 1 in = 25.4 mm. Formula, worked example, table of common values and unit definitions.
Result50.8 mm
1 in = 25.4 mm
2 in =
50.8 mm
Formula
mm = in × 25.4 in = mm × 0.03937007874
Worked example
- 2 in × 25.4 = 50.8 mm
Common values
| in | mm |
|---|---|
| 0.25 | 6.35 |
| 0.5 | 12.7 |
| 1 | 25.4 |
| 2 | 50.8 |
| 4 | 101.6 |
| 12 | 304.8 |
| 36 | 914.4 |
Unit definitions
| Unit | Equals | What it is |
|---|---|---|
| in | 0.0254 m | Inch, exactly 25.4 mm by definition. |
| mm | 0.001 m | Millimetre. Cable sizes, conductor diameters and drawings. |
Frequently asked questions
How many mm are in one in?
1 in = 25.4 mm.
What is the formula to convert in to mm?
mm = in × 25.4. To go back, in = mm × 0.03937007874.
Is the factor exact?
Yes. The inch is defined as exactly 25.4 mm.
Related
Opposite direction: mm to in
Length ConverterAWG to mm²Conversion Centre