Inches to Millimeters Converter (in to mm)
Quickly convert inches to millimeters (in to mm) with high precision. Whether working in engineering, architecture, fabrication, or everyday measurements, use our interactive tool below for instant, accurate calculations.
IN to MM Converter
How to Convert Inches to Millimeters
To convert from inches to millimeters, apply the standard conversion formula:
Formula: millimeters = inches * 25.4
For example, to convert 10 in into mm:
10 in = 254.0 mm
Inches to Millimeters Reference Table
| Inches (in) | Millimeters (mm) |
|---|---|
| 1/16 in (0.0625 in) | 1.5875 mm |
| 1/8 in (0.125 in) | 3.175 mm |
| 1/4 in (0.25 in) | 6.35 mm |
| 1/2 in (0.5 in) | 12.7 mm |
| 3/4 in (0.75 in) | 19.05 mm |
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 10 in | 254 mm |
Practical Applications & Everyday Uses
Converting between inches and millimeters is essential for CNC milling, aerospace tolerances, mechanical fabrication, woodworking, and electronics design when converting US customary dimensions into SI metric specifications.
Frequently Asked Questions
Is the inch to millimeter conversion exact?
Yes. By international agreement established in 1959, 1 international inch is legally defined as exactly 25.4 millimeters.
What is 1/2 inch in millimeters?
1/2 inch (0.5 in) is exactly 12.7 millimeters.