Convert millimetres to inches
1 mm = 0.039 in. Type any value below for an instant conversion.
1 mm = 0.039 in
Formula
in = mm × 0.0393700787Worked example: 50 mm × 0.0393700787 = 1.969 in
Engineering and manufacturing use millimetres almost universally, while US machining still works in thousandths of an inch — one "thou" is 0.0254 mm. Exactly 25.4 mm makes one inch.
millimetres to inches conversion table
| millimetres (mm) | inches (in) |
|---|---|
| 1 mm | 0.039 in |
| 5 mm | 0.197 in |
| 10 mm | 0.394 in |
| 20 mm | 0.787 in |
| 25.4 mm | 1 in |
| 50 mm | 1.969 in |
| 100 mm | 3.937 in |
| 150 mm | 5.906 in |
| 200 mm | 7.874 in |
| 300 mm | 11.811 in |
Frequently asked questions
How many inches are in one millimetre?
One millimetre equals 0.039 inches.
How do I convert millimetres to inches?
Multiply the number of millimetres by 0.0393700787. For example, 50 mm × 0.0393700787 = 1.969 in.
Is this mm to in conversion exact?
The conversion factor of 0.0393700787 is used at full floating-point precision and rounded only for display, so the result is accurate for scientific, engineering and everyday use.
What is the reverse conversion?
Divide by 0.0393700787 instead of multiplying.
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