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Inches to Millimeters
1 in = 25.4 mm. Convert inches (in) to millimeters (mm) with the converter, the formula and the tables below.
Convert inches to millimeters
How to convert inches to millimeters
To convert inches to millimeters, multiply the number of inches by 25.4.
mm = in × 25.4
For example, 5 in = 127 mm.
Inches to millimeters
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
| 250 in | 6,350 mm |
| 500 in | 12,700 mm |
| 1,000 in | 25,400 mm |
Millimeters to inches
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 mm | 0.03937007874 in |
| 2 mm | 0.07874015748 in |
| 3 mm | 0.1181102362 in |
| 4 mm | 0.157480315 in |
| 5 mm | 0.1968503937 in |
| 10 mm | 0.3937007874 in |
| 20 mm | 0.7874015748 in |
| 25 mm | 0.9842519685 in |
| 50 mm | 1.968503937 in |
| 100 mm | 3.937007874 in |
| 250 mm | 9.842519685 in |
| 500 mm | 19.68503937 in |
| 1,000 mm | 39.37007874 in |
Related conversions
Questions
How many millimeters are in one inch?
There are 25.4 millimeters in one inch, and 0.03937007874 inches in one millimeter.
How do I convert inches to millimeters?
To convert inches to millimeters, multiply the number of inches by 25.4. For example, 5 in = 127 mm.
What can I type in the conversion box?
A number, a unit and the unit you want, like “5 ft 10 in to cm”, “72 °F in C”, “3 cups to ml” or “60 mph to km/h”. It understands symbols, full names, plurals and British spellings, adds mixed units such as feet and inches together, and accepts fractions like 1 1/2 or ½. Leave out the second unit to see the value in every common unit.
Which units does the converter know?
448 units in 36 categories: everyday measures of length, weight, volume, temperature, area, speed and time, technical ones like pressure, energy, torque, viscosity and radiation, and regional units such as the Japanese tsubo, Chinese jin, Indian tola and Russian verst.
How accurate are the conversions?
They use exact definitions wherever one exists (an inch is exactly 2.54 cm, a pound exactly 0.45359237 kg) and show 10 significant figures. A few units have varied over time or by region; those are marked, and the value in common modern use is the one used.
Are US and UK gallons the same?
No. A US gallon is 3.785 litres and a UK (imperial) gallon is 4.546 litres, and pints, quarts and fluid ounces differ in the same way. Both are listed separately, and the plain names mean the US ones.
Is a kilobyte 1000 or 1024 bytes?
A kilobyte (kB) is 1000 bytes, as with every other metric prefix. 1024 bytes is a kibibyte (KiB), and the same goes for MB and MiB, GB and GiB. Disk makers use the first; many operating systems show the second, which is why a 1 TB drive shows up as about 931 GB.
Why can't I convert cups to grams, or kilograms to litres?
Volume and weight measure different things, so the answer depends on what's being measured: a cup of flour weighs far less than a cup of honey. The converter only converts between units of the same kind, and tells you when two units can't be converted.
Part of Unit Converter
Convert over 400 units of length, weight, temperature, volume, speed, pressure, energy and more. Or just type a conversion like “5 ft 10 in to cm”.
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