Convert mm to inches (2024)

Convert mm to inches (1)

Home / Length Conversion / Convert mm to inches

Please provide values below to convert millimeter [mm] to inch [in], or vice versa.


Definition: A millimeter (symbol: mm) is a unit of length in the International System of Units (SI). It is defined in terms of the meter, as 1/1000 of a meter, or the distance traveled by light in 1/299 792 458 000 of a second.

History/origin: The milli- prefix is one of many metric prefixes. It indicates one thousandth of the base unit, in this case the meter. The definition of the meter has changed over time, the current definition being based on the distance traveled by the speed of light in a given amount of time. The relationship between the meter and the millimeter is constant however. Prior to this definition, the meter was based on the length of a prototype meter bar. In 2019, the meter has been re-defined based on the changes made to the definition of a second.


Definition: An inch (symbol: in) is a unit of length in the imperial and US customary systems of measurement. An inch was defined to be equivalent to exactly 25.4 millimeters in 1959. There are 12 inches in a foot and 36 inches in a yard.

History/origin: The term "inch" was derived from the Latin unit "uncia" which equated to "one-twelfth" of a Roman foot.

There have been a number of different standards for the inch in the past, with the current definition being based on the international yard. One of the earliest definitions of the inch was based on barleycorns, where an inch was equal to the length of three grains of dry, round barley placed end-to-end. Another version of the inch is also believed to have been derived from the width of a human thumb, where the length was obtained from averaging the width of three thumbs: a small, a medium, and a large one.

Current use: The inch is mostly used in the United States, Canada, and the United Kingdom. It is also sometimes used in Japan (as well as other countries) in relation to electronic parts, like the size of display screens.

Millimeter to Inch Conversion Table

Millimeter [mm]Inch [in]
0.01 mm0.0003937008 in
0.1 mm0.0039370079 in
1 mm0.0393700787 in
2 mm0.0787401575 in
3 mm0.1181102362 in
5 mm0.1968503937 in
10 mm0.3937007874 in
20 mm0.7874015748 in
50 mm1.968503937 in
100 mm3.937007874 in
1000 mm39.3700787402 in

How to Convert Millimeter to Inch

1 mm = 0.0393700787 in
1 in = 25.4 mm

Example: convert 15 mm to in:
15 mm = 15 × 0.0393700787 in = 0.5905511811 in

Popular Length Unit Conversions

cm to inches

inches to cm

mm to inches

inches to mm

meters to feet

feet to meters

km to miles

miles to km

cm to feet

feet to cm

inches to feet

feet to inches

meters to yards

yards to meters

mm to cm

cm to mm

cm to m

m to cm

cm to km

km to cm

mm to feet

feet to mm

meters to miles

miles to meters

feet to miles

miles to feet

yards to feet

inches to meters

meters to inches

mm to m

m to mm

km to m

m to km

inches to yards

yards to inches

yards to miles

miles to yards

Convert Millimeter to Other Length Units

mm to m

Millimeter to Kilometer

Millimeter to Decimeter

mm to cm

Millimeter to Micrometer

Millimeter to Nanometer

Millimeter to Mile

Millimeter to Yard

mm to feet

Millimeter to Light Year

Millimeter to Break

Millimeter to Exameter

Millimeter to Petameter

Millimeter to Terameter

Millimeter to Gigameter

Millimeter to Megameter

Millimeter to Hectometer

Millimeter to Dekameter

Millimeter to Micron

Millimeter to Picometer

Millimeter to Femtometer

Millimeter to Attometer

Millimeter to Megaparsec

Millimeter to Kiloparsec

Millimeter to Parsec

Millimeter to Astronomical Unit

Millimeter to League

Millimeter to Nautical League (UK)

Millimeter to Nautical League (int.)

Millimeter to League (statute)

Millimeter to Nautical Mile (UK)

Millimeter to Nautical Mile (international)

Millimeter to Mile (statute)

Millimeter to Mile (US Survey)

Millimeter to Mile (Roman)

Millimeter to Kiloyard

Millimeter to Furlong

Millimeter to Furlong (US Survey)

Millimeter to Chain

Millimeter to Chain (US Survey)

Millimeter to Rope

Millimeter to Rod

Millimeter to Rod (US Survey)

Millimeter to Perch

Millimeter to Pole

Millimeter to Fathom

Millimeter to Fathom (US Survey)

Millimeter to Ell

Millimeter to Foot (US Survey)

Millimeter to Link

Millimeter to Link (US Survey)

Millimeter to Cubit (UK)

Millimeter to Hand

Millimeter to Span (cloth)

Millimeter to Finger (cloth)

Millimeter to Nail (cloth)

Millimeter to Inch (US Survey)

Millimeter to Barleycorn

Millimeter to Mil

Millimeter to Microinch

Millimeter to Angstrom

Millimeter to A.u. Of Length

Millimeter to X-unit

Millimeter to Fermi

Millimeter to Arpent

Millimeter to Pica

Millimeter to Point

Millimeter to Twip

Millimeter to Aln

Millimeter to Famn

Millimeter to Caliber

Millimeter to Centiinch

Millimeter to Ken

Millimeter to Russian Archin

Millimeter to Roman Actus

Millimeter to Vara De Tarea

Millimeter to Vara Conuquera

Millimeter to Vara Castellana

Millimeter to Cubit (Greek)

Millimeter to Long Reed

Millimeter to Reed

Millimeter to Long Cubit

Millimeter to Handbreadth

Millimeter to Fingerbreadth

Millimeter to Planck Length

Millimeter to Electron Radius (classical)

Millimeter to Bohr Radius

Millimeter to Earth's Equatorial Radius

Millimeter to Earth's Polar Radius

Millimeter to Earth's Distance From Sun

Millimeter to Sun's Radius

Convert mm to inches (2024)


Convert mm to inches? ›

How can you estimate the conversion from millimeters to inches? There are 25.4 millimeters in an inch. For a quick conversion and estimation, we can divide the length in millimeters by 25. For example, 100 mm is approximately equal to 100 ÷ 25 = 4 inches.

How many mm are in 1 inch exactly? ›

One inch is equal to 25.4 millimeters.

Is 30 mm one inch? ›

How do you convert millimeters to inches? Since there are 25.4 millimeters in one inch, the length in inches is equal to millimeters divided by 25.4.

Is 20 mm the same as 1 inch? ›

Answer: 20 millimeters is equal to approximately 0.7874 inches. Here's how the calculation is done: Given Measurement: 20 mm. Conversion Factor: 1 inch = 25.4 mm.

How many mm is 1⁄8 inch? ›

3.18 mm

What is the proper conversion factor to convert inches to millimeters? ›

To convert inches to mm, you must multiply the unit by 25.4. For instance, if you have to convert 10 inches to mm, you need to multiply 10 with 25.4. Here are some popular metrics related to 1 inch.

How many mm is 1 ⁄ 4 inch? ›

To convert 1/4 inch to mm, divide 1 by 4 to convert the fraction to a decimal. Then, multiply that by 25.4 since there are 25.4 millimeters in one inch. That's the formula that our calculator uses to find that 1/4 inch to millimeters is 6.35 mm.

How many mm is 1 ⁄ 2 inch? ›

Inches to millimeters conversion table
Inches (")Millimeters (mm)
1/2 ″12.7 mm
1 ″25.4 mm
2 ″50.8 mm
3 ″76.2 mm
23 more rows

Is 10 mm the same as 1 inch? ›

10mm = just over 3/8 inch. 11mm = almost 7/16 inch.

How wide is 50 mm in inches? ›

MM to Inches Formula and Example
20 MM is equal to 20* 0.0390.787 Inches
50 MM is equal to 50* 0.0391.969 Inches
75 MM is equal to 75* 0.0392.953 Inches
100 MM is equal to 100* 0.0393.937 Inches
5 more rows

Top Articles
Latest Posts
Article information

Author: Horacio Brakus JD

Last Updated:

Views: 5927

Rating: 4 / 5 (71 voted)

Reviews: 94% of readers found this page helpful

Author information

Name: Horacio Brakus JD

Birthday: 1999-08-21

Address: Apt. 524 43384 Minnie Prairie, South Edda, MA 62804

Phone: +5931039998219

Job: Sales Strategist

Hobby: Sculling, Kitesurfing, Orienteering, Painting, Computer programming, Creative writing, Scuba diving

Introduction: My name is Horacio Brakus JD, I am a lively, splendid, jolly, vivacious, vast, cheerful, agreeable person who loves writing and wants to share my knowledge and understanding with you.