Inch to Millimeter Formula
The complete formula for converting inches (in) to millimeters (mm). See the formula, how it works, and worked examples below.
in × 25.4 = mm
How the Formula Works
To convert inches to millimeters, multiply the value by 25.4. This works because 1 inch equals 25.4 millimeters.
Worked Examples
1 in to mm
- Start with 1 in
- Multiply by 25.4: 1 × 25.4 = 25.4
- Result: 1 in = 25.4 mm
5 in to mm
- Start with 5 in
- Multiply by 25.4: 5 × 25.4 = 127
- Result: 5 in = 127 mm
10 in to mm
- Start with 10 in
- Multiply by 25.4: 10 × 25.4 = 254
- Result: 10 in = 254 mm
50 in to mm
- Start with 50 in
- Multiply by 25.4: 50 × 25.4 = 1,270
- Result: 50 in = 1,270 mm
100 in to mm
- Start with 100 in
- Multiply by 25.4: 100 × 25.4 = 2,540
- Result: 100 in = 2,540 mm
Reverse Formula: Millimeter to Inch
mm ÷ 25.4 = in
See the full Millimeter to Inch formula for worked examples.
Related
Frequently Asked Questions
The formula is: in × 25.4 = mm. See the worked examples above for step-by-step breakdowns, or use the Inch to Millimeter converter for instant results.
10 inches = 254 millimeters. Apply the formula: in × 25.4 = mm.