Convert
Millimeter to Inch Converter
1 mm = 25.4 in · exact factor
Frommm
→=
Toin
0.1575
formulain = mm × 0.03937007874015748
Quick conversions
Common conversions
| mm | in |
|---|---|
| 1 mm | 0.0394 in |
| 5 mm | 0.1969 in |
| 10 mm | 0.3937 in |
| 20 mm | 0.7874 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.9370 in |
About this conversion
Millimeters and inches both appear in precision contexts, but they come from opposing measurement traditions. Millimeters are the default in engineering, manufacturing, and technical specifications worldwide — tolerances on machined parts, thread pitches, and bolt diameters are nearly always given in mm outside the US. Inches dominate American hardware: drill bits, pipe fittings, and lumber dimensions. 1 inch equals exactly 25.4 mm. This means a 1/4-inch bolt has a 6.35 mm diameter, and a standard 3/8-inch drill bit is 9.525 mm. For machinists and woodworkers collaborating across borders, this conversion is routine.
Examples
- →4 mm to in = 0.1575 in
- →4 mm in in is 0.1575 in
- →4 mm equals 0.1575 in
- →Convert 4 mm to in: 0.1575 in
- →How much is 4 mm in in? 0.1575 in
- →What is 4 mm in in? 0.1575 in
- →4 mm converted to in is 0.1575 in
- →0.1575 in is equal to 4 mm
Frequently asked questions
1 millimeter is equal to exactly 0.03937007874015748 inch (and conversely, 1 inch = 25.4 millimeter). This factor is fixed by international definition and does not vary.