What this conversion means in practice
Drawings in millimeters are standard in most factories; US maintenance still stocks inch wrenches. Twenty-five point four millimeters is exactly one inch.
Nine hundred fourteen point four mm is three feet (914.4 mm = 3 × 304.8 mm). A 6 mm bolt is about 0.236 in, not half an inch.
Stack tolerances in one unit system before converting the final result, not each intermediate step.
How to convert millimeter to inch
Multiply the millimeter value by 0.03937007874 to get inch.
Example: 25.4 mm × 0.03937007874 = 1 inches
Millimeter
Definition: A millimeter (mm) equals one-thousandth of a meter.
History and origin: Adopted widely where metric precision is needed without fractions.
Current use: Used in machining, manufacturing, drafting, and tolerancing.
Inch
Definition: An inch (in) equals 0.0254 meters exactly.
History and origin: Historically varied; now fixed relative to the meter for consistency.
Current use: Used for displays, hardware dimensions, and many US specifications.
Millimeter to Inch conversion table
| Millimeter (mm) | Inch (inches) |
|---|---|
| 0.1 mm | 0.0039370079 inches |
| 1 mm | 0.0393700787 inches |
| 2 mm | 0.0787401575 inches |
| 3 mm | 0.1181102362 inches |
| 5 mm | 0.1968503937 inches |
| 10 mm | 0.3937007874 inches |
| 20 mm | 0.7874015748 inches |
| 50 mm | 1.968503937 inches |
| 100 mm | 3.937007874 inches |
| 1,000 mm | 39.3700787402 inches |
Millimeter to Inch FAQ
mm to inches for shop work, 3D prints, and fastener catalogs.
How many inches is 10 mm?
About 0.394 in (10 ÷ 25.4).
Is this the same as cm to inches?
Same definition: 25.4 mm = 1 in = 2.54 cm.
Thousandths of an inch?
Divide mm by 25.4, then multiply by 1,000 for µin-style reads, or work in mils per your shop convention.