MM ↔ Inches Converter
Precise to 5 decimal places
Additional Conversion Tools
CM ↔ Inches
Feet ↔ Meters
Inches ↔ Points
MM ↔ Pixels
Quick Reference Table
| Millimeters | Inches | Millimeters | Inches |
|---|---|---|---|
| 1 mm | 0.03937 in | 25.4 mm | 1 in |
| 5 mm | 0.19685 in | 50.8 mm | 2 in |
| 10 mm | 0.3937 in | 76.2 mm | 3 in |
| 15 mm | 0.59055 in | 100 mm | 3.93701 in |
| 20 mm | 0.7874 in | 254 mm | 10 in |
MM to Inches Conversion Guide
The millimeter to inch conversion is used in manufacturing, construction, product design, and print workflows where metric and imperial dimensions must match exactly. This page is built as a practical reference with formulas, worked examples, and a quick table so you can convert mm to inches with confidence.
How to Convert MM to Inches
Use this exact formula:
inches = millimeters / 25.4
Since one inch is exactly 25.4 millimeters, dividing by 25.4 gives precise inch values for any mm input.
Calculation Steps and Examples
Example 1: Convert 10 mm to inches.
10 / 25.4 = 0.39370 in
Example 2: Convert 50 mm to inches.
50 / 25.4 = 1.96850 in
Example 3: Convert 100 mm to inches.
100 / 25.4 = 3.93701 in
Millimeter and Inch Definitions
Millimeter (mm): One millimeter is one thousandth of a meter and one tenth of a centimeter.
Inch (in): One inch is one twelfth of a foot and equals exactly 25.4 millimeters.
These exact relationships make conversions stable for engineering drawings, CAD files, and dimensional checks.
Common MM to Inches Values
| Millimeters (mm) | Inches (in) | Millimeters (mm) | Inches (in) |
|---|---|---|---|
| 1 | 0.03937 | 30 | 1.18110 |
| 2 | 0.07874 | 40 | 1.57480 |
| 5 | 0.19685 | 60 | 2.36220 |
| 10 | 0.39370 | 80 | 3.14961 |
| 20 | 0.78740 | 100 | 3.93701 |
Length Conversion Tools Index
Use these dedicated pages for detailed formulas, examples, and conversion contexts. Each page links back to this homepage to keep mm to inches as the main reference.
Frequently Asked Questions
How many inches are in 1 mm?
1 mm equals 0.03937 inches.
How many mm are in 1 inch?
1 inch equals exactly 25.4 mm.
Is the mm to inches conversion exact?
Yes. The base relationship of 1 in = 25.4 mm is exact. Differences only come from rounding displayed results.