Inches to Millimeters Converter
Convert inches to millimeters.
Result
0
Millimeters
1 Inches = 25.4 Millimeters
How to convert Inches to Millimeters?
How many Millimeters are in a Inches? The key relationship is:
- 1 Inch = 25.4 Millimeters
- 1 Millimeter = 0.0393701 Inches
To convert Inches to Millimeters, multiply the value by 25.4.
Formula: Millimeters = Inches × 25.4
Step-by-Step Calculation
- Take the number of Inches you want to convert (e.g., 4).
- Multiply that value by 25.4.
- The result is the value in Millimeters. (Example: 4 × 25.4 = 101.6 Millimeters).
How to use this converter?
Enter inches and instantly get millimeters—useful for engineering, tools, and precise measurements.
Common Inches to Millimeters Conversions
Quick reference guide for common inch sizes.
0.5 Inch = 12.7 mm
1 Inch = 25.4 mm
2 Inches = 50.8 mm
3 Inches = 76.2 mm
4 Inches = 101.6 mm
6 Inches = 152.4 mm
8 Inches = 203.2 mm
10 Inches = 254 mm
12 Inches = 304.8 mm
24 Inches = 609.6 mm
History: How were inches standardized?
Inches were historically based on physical references, but modern standards define them precisely using metric equivalents—so conversions remain consistent worldwide.
Common Inches to Millimeters Conversions
| Inches Input | Millimeters Result |
|---|---|
| 0.5 Inch | 12.7 mm |
| 1 Inch | 25.4 mm |
| 2 Inches | 50.8 mm |
| 3 Inches | 76.2 mm |
| 4 Inches | 101.6 mm |
| 6 Inches | 152.4 mm |
| 8 Inches | 203.2 mm |
| 10 Inches | 254 mm |
| 12 Inches | 304.8 mm |
| 24 Inches | 609.6 mm |
Frequently Asked Questions
How do I convert inches to millimeters?
Multiply inches by 25.4 to get millimeters.
How many mm is 1 inch?
1 inch equals exactly 25.4 mm.
How many mm is 4 inches?
4 inches equals 101.6 mm.
How many mm is 12 inches?
12 inches equals 304.8 mm.
Is the conversion exact?
Yes—because 1 inch is defined as exactly 25.4 millimeters.