UtilityBaseCalculators
MM to Inches Converter
Convert millimeters to inches and back — edit either box, both update.
Updated July 10, 2026
How to use the mm to inches converter
- 1Enter a value in millimeters.
- 2Read the equivalent in inches.
- 3Or type an inches value to convert the other way.
- 4Check the reference table for common sizes.
Common uses
- Converting part or hardware dimensions
- 3D printing and CAD measurements
- Woodworking and machining specs
- Jewelry and small-object sizing
Frequently asked questions
How many inches is 1 mm?
One millimeter is about 0.03937 inches, since there are exactly 25.4 millimeters in an inch. To convert millimeters to inches, divide by 25.4; to go from inches to millimeters, multiply by 25.4.
How many mm are in an inch?
Exactly 25.4 millimeters. So a quarter inch is 6.35 mm and a half inch is 12.7 mm. The relationship is exact by definition, so conversions are precise.
Why use mm instead of cm?
Millimeters give finer precision for small parts, which is why they dominate engineering, 3D printing, and hardware specs. This converter keeps that precision when moving those measurements to inches.
About this tool
The mm to inches converter turns millimeters into inches and inches into millimeters instantly. There are exactly 25.4 millimeters in an inch, so millimeters convert to inches by dividing by 25.4. Edit either field and the other updates live, with a quick-reference table. It's the precise-measurement conversion used in woodworking, 3D printing, machining, hardware, and jewelry, where small dimensions move between metric and imperial. Everything is calculated in your browser.
Like most tools on UtilityBase, the mm to inches converter runs entirely in your browser — nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more calculators here.
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