Length converter
Convert Thousandths of an Inch to Millimeters (thou to mm)
1 thou = 0.0254 mm. Tolerances and coating thickness, where a thou is 0.001 inch.
Thousandths of an inch to millimeters conversion table
| thou | mm |
|---|---|
| 0.5 thou | 0.0127 mm |
| 1 thou | 0.0254 mm |
| 1.5 thou | 0.0381 mm |
| 2 thou | 0.0508 mm |
| 2.5 thou | 0.0635 mm |
| 3 thou | 0.0762 mm |
| 4 thou | 0.1016 mm |
| 5 thou | 0.127 mm |
| 6 thou | 0.1524 mm |
| 7 thou | 0.1778 mm |
| 8 thou | 0.2032 mm |
| 9 thou | 0.2286 mm |
| 10 thou | 0.254 mm |
| 12 thou | 0.3048 mm |
| 15 thou | 0.381 mm |
| 18 thou | 0.4572 mm |
| 20 thou | 0.508 mm |
| 25 thou | 0.635 mm |
| 30 thou | 0.762 mm |
| 35 thou | 0.889 mm |
| 40 thou | 1.016 mm |
| 45 thou | 1.143 mm |
| 50 thou | 1.27 mm |
| 60 thou | 1.524 mm |
| 62.5 thou | 1.5875 mm |
| 70 thou | 1.778 mm |
| 75 thou | 1.905 mm |
| 80 thou | 2.032 mm |
| 90 thou | 2.286 mm |
| 100 thou | 2.54 mm |
| 125 thou | 3.175 mm |
| 150 thou | 3.81 mm |
| 187.5 thou | 4.7625 mm |
| 200 thou | 5.08 mm |
| 250 thou | 6.35 mm |
| 375 thou | 9.525 mm |
| 500 thou | 12.7 mm |
| 750 thou | 19.05 mm |
| 1000 thou | 25.4 mm |
How to convert thousandths of an inch to millimeters
Multiply the value in thousandths of an inch by 0.0254 to get millimeters. 1 thou equals 0.0254 mm, and 1 mm equals 39.3701 thou.
About these units
A thou (or mil) is one thousandth of an inch, written 0.001 in. Machinists quote fits, shim sizes, and coating thicknesses in thou.
The millimeter is one thousandth of a meter and the default dimension unit on metric engineering drawings. Machined tolerances are commonly quoted in hundredths of a millimeter.
Common questions
How many millimeters are in a thousandth of an inch?
1 thou equals 0.0254 mm.
How do you convert thousandths of an inch to millimeters?
Use mm = thou × 0.0254. So 1 thou = 0.0254 mm, and to go back, 1 mm = 39.3701 thou.
What is 5 thou in mm?
5 thou equals 0.127 mm.
What is 10 thou in mm?
10 thou equals 0.254 mm.
What is 20 thou in mm?
20 thou equals 0.508 mm.