Inches to Millimeters (in → mm)
Formula
1 in = 25.4 mmConversion Table
| in | mm |
|---|---|
| 0 | 0 |
| 1.0000 | 25.400 |
| 2.0000 | 50.800 |
| 3.0000 | 76.200 |
| 4.0000 | 101.60 |
| 5.0000 | 127.00 |
| 6.0000 | 152.40 |
| 7.0000 | 177.80 |
| 8.0000 | 203.20 |
| 9.0000 | 228.60 |
| 10.000 | 254.00 |
| 11.000 | 279.40 |
| 12.000 | 304.80 |
| 13.000 | 330.20 |
| 14.000 | 355.60 |
| 15.000 | 381.00 |
| 16.000 | 406.40 |
| 17.000 | 431.80 |
| 18.000 | 457.20 |
| 19.000 | 482.60 |
| in | mm |
|---|---|
| 20.000 | 508.00 |
| 21.000 | 533.40 |
| 22.000 | 558.80 |
| 23.000 | 584.20 |
| 24.000 | 609.60 |
| 25.000 | 635.00 |
| 26.000 | 660.40 |
| 27.000 | 685.80 |
| 28.000 | 711.20 |
| 29.000 | 736.60 |
| 30.000 | 762.00 |
| 31.000 | 787.40 |
| 32.000 | 812.80 |
| 33.000 | 838.20 |
| 34.000 | 863.60 |
| 35.000 | 889.00 |
| 36.000 | 914.40 |
| 37.000 | 939.80 |
| 38.000 | 965.20 |
| 39.000 | 990.60 |
| in | mm |
|---|---|
| 40.000 | 1,016.0 |
| 41.000 | 1,041.4 |
| 42.000 | 1,066.8 |
| 43.000 | 1,092.2 |
| 44.000 | 1,117.6 |
| 45.000 | 1,143.0 |
| 46.000 | 1,168.4 |
| 47.000 | 1,193.8 |
| 48.000 | 1,219.2 |
| 49.000 | 1,244.6 |
| 50.000 | 1,270.0 |
| 51.000 | 1,295.4 |
| 52.000 | 1,320.8 |
| 53.000 | 1,346.2 |
| 54.000 | 1,371.6 |
| 55.000 | 1,397.0 |
| 56.000 | 1,422.4 |
| 57.000 | 1,447.8 |
| 58.000 | 1,473.2 |
| 59.000 | 1,498.6 |
| in | mm |
|---|---|
| 60.000 | 1,524.0 |
| 61.000 | 1,549.4 |
| 62.000 | 1,574.8 |
| 63.000 | 1,600.2 |
| 64.000 | 1,625.6 |
| 65.000 | 1,651.0 |
| 66.000 | 1,676.4 |
| 67.000 | 1,701.8 |
| 68.000 | 1,727.2 |
| 69.000 | 1,752.6 |
| 70.000 | 1,778.0 |
| 71.000 | 1,803.4 |
| 72.000 | 1,828.8 |
| 73.000 | 1,854.2 |
| 74.000 | 1,879.6 |
| 75.000 | 1,905.0 |
| 76.000 | 1,930.4 |
| 77.000 | 1,955.8 |
| 78.000 | 1,981.2 |
| 79.000 | 2,006.6 |
Inches to Millimeters Conversion
Converting Inches (in) to Millimeters (mm) is a common length conversion. 1 in equals 25.4 mm. For example, 100 in is equal to 2,540 mm.
Quick Mental Math: Inches to Millimeters
Multiply inches by 25.4 to estimate millimeters.
Why is converting Inches to Millimeters tricky?
The irregular conversion factor is difficult to memorize or estimate mentally.
Quick Reference Values
1 in = 25.4 mm. 5 in = 127 mm. 10 in = 254 mm. 25 in = 635 mm. 50 in = 1,270 mm. 100 in = 2,540 mm.
What is Inches?
Inches (in) is a unit of length. The inch is a unit of length in the imperial and US customary systems, defined exactly as 25.4 millimeters. It is used primarily for measuring small dimensions in construction, manufacturing, and personal height in the US and UK. The exact definition ensures consistent conversion to metric units [nist-si-guide]. The inch traces back to ancient Roman and English measurements, historically based on thumb width. The current exact definition of 25.4 mm was internationally agreed upon in 1959 by the US, UK, Canada, and others to standardize measurements [nist-si-guide]. Inches are primarily used in the United States, Canada, and the United Kingdom for construction, manufacturing, and consumer goods. Internationally, industries convert inches to millimeters for precision and standardization, following ISO and NIST guidelines [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: inch, inches, inchess, inchs, inche, milimeters, milimeter, millimter, mm. All of these refer to the Inches to Millimeters conversion.