Thou (Mils) to Millimeters (th → mm)
Formula
1 th = 0.0254 mmConversion Table
| th | mm |
|---|---|
| 0 | 0 |
| 1.0000 | 0.025400 |
| 2.0000 | 0.050800 |
| 3.0000 | 0.076200 |
| 4.0000 | 0.10160 |
| 5.0000 | 0.12700 |
| 6.0000 | 0.15240 |
| 7.0000 | 0.17780 |
| 8.0000 | 0.20320 |
| 9.0000 | 0.22860 |
| 10.000 | 0.25400 |
| 11.000 | 0.27940 |
| 12.000 | 0.30480 |
| 13.000 | 0.33020 |
| 14.000 | 0.35560 |
| 15.000 | 0.38100 |
| 16.000 | 0.40640 |
| 17.000 | 0.43180 |
| 18.000 | 0.45720 |
| 19.000 | 0.48260 |
| th | mm |
|---|---|
| 20.000 | 0.50800 |
| 21.000 | 0.53340 |
| 22.000 | 0.55880 |
| 23.000 | 0.58420 |
| 24.000 | 0.60960 |
| 25.000 | 0.63500 |
| 26.000 | 0.66040 |
| 27.000 | 0.68580 |
| 28.000 | 0.71120 |
| 29.000 | 0.73660 |
| 30.000 | 0.76200 |
| 31.000 | 0.78740 |
| 32.000 | 0.81280 |
| 33.000 | 0.83820 |
| 34.000 | 0.86360 |
| 35.000 | 0.88900 |
| 36.000 | 0.91440 |
| 37.000 | 0.93980 |
| 38.000 | 0.96520 |
| 39.000 | 0.99060 |
| th | mm |
|---|---|
| 40.000 | 1.0160 |
| 41.000 | 1.0414 |
| 42.000 | 1.0668 |
| 43.000 | 1.0922 |
| 44.000 | 1.1176 |
| 45.000 | 1.1430 |
| 46.000 | 1.1684 |
| 47.000 | 1.1938 |
| 48.000 | 1.2192 |
| 49.000 | 1.2446 |
| 50.000 | 1.2700 |
| 51.000 | 1.2954 |
| 52.000 | 1.3208 |
| 53.000 | 1.3462 |
| 54.000 | 1.3716 |
| 55.000 | 1.3970 |
| 56.000 | 1.4224 |
| 57.000 | 1.4478 |
| 58.000 | 1.4732 |
| 59.000 | 1.4986 |
| th | mm |
|---|---|
| 60.000 | 1.5240 |
| 61.000 | 1.5494 |
| 62.000 | 1.5748 |
| 63.000 | 1.6002 |
| 64.000 | 1.6256 |
| 65.000 | 1.6510 |
| 66.000 | 1.6764 |
| 67.000 | 1.7018 |
| 68.000 | 1.7272 |
| 69.000 | 1.7526 |
| 70.000 | 1.7780 |
| 71.000 | 1.8034 |
| 72.000 | 1.8288 |
| 73.000 | 1.8542 |
| 74.000 | 1.8796 |
| 75.000 | 1.9050 |
| 76.000 | 1.9304 |
| 77.000 | 1.9558 |
| 78.000 | 1.9812 |
| 79.000 | 2.0066 |
Thou (Mils) to Millimeters Conversion
Converting Thou (Mils) (th) to Millimeters (mm) is a common length conversion. 1 th equals 0.0254 mm. For example, 100 th is equal to 2.54 mm.
Quick Mental Math: Thou (Mils) to Millimeters
Reference a linear anchor between thou and millimeters; use one memorable value.
Why is converting Thou (Mils) to Millimeters tricky?
Magnitude or direction confusion between thou and millimeters is the primary error source.
Quick Reference Values
1 th = 0.0254 mm. 5 th = 0.127 mm. 10 th = 0.254 mm. 25 th = 0.635 mm. 50 th = 1.27 mm. 100 th = 2.54 mm.
What is Thou (Mils)?
Thou (Mils) (th) is a unit of length. A thou is a unit of length equal to one thousandth of an inch (0.001 in). It corresponds to exactly 25.4 micrometers (µm) in SI units. The thou is widely used in engineering and manufacturing for precise measurements of thickness and diameter [nist-si-guide]. The thou emerged in the 19th century in British engineering as a convenient subdivision of the inch. Its use was formalized to provide accuracy in machining and toolmaking, reflecting industrial measurement needs [nist-si-guide]. The thou remains common in the United States, Canada, and the UK for mechanical engineering and machining tolerances. It is frequently used in the automotive and aerospace industries for component specifications [nist-si-guide].
What is Millimeters?
Millimeters (mm) is a unit of length. A millimeter (mm) is a unit of length equal to one-thousandth of a meter, the SI base unit of length. It measures small distances and thicknesses with precision in engineering, manufacturing, and construction [bipm-si-brochure]. One millimeter equals exactly 0.001 meters or 10^-3 meters. The meter was defined in 1793 during the French Revolution, with the millimeter introduced as a decimal subdivision in the metric system. International standards bodies like BIPM later formalized its exact value to maintain global uniformity [bipm-si-brochure]. Millimeters are used worldwide in technical drawings, engineering specifications, and everyday measurements such as clothing and manufacturing tolerances. ISO standards mandate millimeter precision in many industrial applications [iso-80000].
Common Misspellings
People often search for this conversion using these alternate spellings: thow, thouh, thous, milimeters, milimeter, millimter, mm. All of these refer to the Thou (Mils) to Millimeters conversion.