Convert millimetres to inches (or inches to millimetres) instantly — essential for engineering, woodworking, mechanical fittings, photography (lens thread sizes), product specifications, and any technical work where precision matters across metric and imperial systems. All calculations run in your browser.
One millimetre equals 0.0393701 inches. Conversely, one inch equals 25.4 millimetres.
Yes. The tool works in both directions — enter a value in either field for the instant conversion.
25.4 mm equals exactly 1 inch. This is the defined conversion factor.
Yes. Drill bits and bolts come in both metric (mm) and imperial (inch) sizes. Use this converter to find the nearest equivalent when switching between standards.
No. All conversions run entirely in your browser with no server communication.
Formula: 1 mm = 0.03937 inches