# Inches to MM

How many mm to 1 inch? According to the internationally recognized length unit conversion standard, one inch is equal to 25.4 millimeters. Write the conversion relationship between inches and millimeters as a formula, that is, 1 inch = 25.4 mm.

This official, standardized metric conversion standard has its origins in the 1959 International Measurement and Recording Record of Weights and Measures.

### How to Convert Inches to MM?

1 in = 25.4 mm

For example: Convert 2 inches to mm

2 in = 2 × 25.4 = 50.8 cm

### Inch Definition

Anglo-American units of length are in inches. 12 inches equals 1 foot, while 36 inches equals 1 yard. Modern standards say that one inch equals 2.54 centimeters.

In the liquid crystal display, the specifications are generally 17 inches, 19 inches, 23 inches, 27 inches and so on. In mobile phones, the screen sizes are generally 4.0 inches, 4.2 inches, 4.5 inches, 4.7 inches, 4.8 inches, 5.0 inches, 5.2 inches, 5.5 inches, 5.7 inches, 6.44 inches and so on. In tablet computers, the screen sizes are generally 7.9 inches, 9.7 inches, and 12.9 inches. The size of the display is measured in terms of the length of the diagonal, in “inches”.

### Millimeter Definition

Millimeters are a unit of length measurement and a unit of rainfall. The English abbreviation is mm. 1 mm is equivalent to one thousandth of a meter, one hundredth of a decimeter, and one tenth of a centimeter.

One of the many metric prefixes is the milli-prefix. It is one thousandth of the base unit. In this case, it is the meter. Over time, the definition of a meter has changed. The current definition is based on how far one can travel at the speed of light over a certain time period. However, the relationship between the millimeter and the meter remains constant. The length of a prototype bar meter was the basis for the definition of the meter. The definition of a second has changed in 2019, and the meter was re-defined.