Millimeter to inch conversion
MM to Inches Converter
Convert millimeters to inches for hardware, small parts, technical drawings, product specs, and metric-to-imperial size checks.
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in
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10 mm = 0.39370079 in
10 mm × 0.03937008 = 0.39370079 in
Decimal inches0.39370079 in
Feet + inches0 ft 0.3937 in
Nearest 1/16 inch3/8"
10 mm = 0.3937 inches
millimeters / 25.4 = inches
How to convert millimeters to inches
Divide the millimeter value by exactly 25.4. The factor is exact because one inch is defined as exactly 25.4 millimeters.
Common mm to inches examples
| Millimeters | Inches | Use case |
|---|---|---|
| 2 mm | 0.0787 inches | Thin parts, small gaps, and close tolerances. |
| 5 mm | 0.1969 inches | Small hardware and compact product details. |
| 10 mm | 0.3937 inches | A common metric size close to four-tenths of an inch. |
| 25.4 mm | 1 inch | Exact inch reference. |
| 100 mm | 3.937 inches | One-tenth of a meter in inches. |
Who this tool is for
- People comparing metric hardware, fasteners, small parts, and product dimensions with inch-based specs.
- Makers, repair users, students, and shoppers who need readable decimal inches from millimeters.
- Anyone checking whether a small metric measurement is close to a familiar inch or fractional-inch size.
Related tools
For exact factors and rounding, review the conversion methodology.
Frequently asked questions
How do I convert mm to inches?
Divide the millimeter value by 25.4 to get inches.
How many inches is 10 mm?
10 mm is approximately 0.3937 inches.
Is 25.4 mm exactly 1 inch?
Yes. One inch is defined as exactly 25.4 millimeters.
When should I use millimeters instead of centimeters?
Use millimeters for small parts, hardware, drawings, and dimensions where centimeter rounding is too coarse.