How many mm in an inch?

1 inch = 25.4 mm

One inch is equal to 25.4 millimeters.

Inches to mm converter

Convert 1 inch to mm

To convert 1 inch to millimeters, you first need to know the conversion factor between inch and millimeters. According to the standard, 1 inch equals exactly 25.4 millimeters.

So, to figure out how many millimeters are in an inch, you simply multiply the number of inch by 25.4.

Calculation: 1 inch to millimeters

1 × 25.4 = 25.4 mm

This means an inch equals 25.4 mm. For a better idea of how long that really is, check out how long is an inch?

Definitions

Inch (in): An inch equals 2.54 centimeters. Widely used in the U.S., Canada, and the UK for screen sizes, furniture dimensions, and smaller household items.

Millimeter (mm): A millimeter is one-thousandth of a meter (0.001 m). Often used for precision measurements in engineering, manufacturing, and product design.

Convert 1 inch to other lengths

Inches to mm conversion table

Inches (in)Millimeters (mm)
0.51 in12.954 mm
0.52 in13.208 mm
0.53 in13.462 mm
0.54 in13.716 mm
0.55 in13.97 mm
0.56 in14.224 mm
0.57 in14.478 mm
0.58 in14.732 mm
0.59 in14.986 mm
0.6 in15.24 mm
0.61 in15.494 mm
0.62 in15.748 mm
0.63 in16.002 mm
0.64 in16.256 mm
0.65 in16.51 mm
0.66 in16.764 mm
0.67 in17.018 mm
0.68 in17.272 mm
0.69 in17.526 mm
0.7 in17.78 mm
0.71 in18.034 mm
0.72 in18.288 mm
0.73 in18.542 mm
0.74 in18.796 mm
0.75 in19.05 mm
0.76 in19.304 mm
0.77 in19.558 mm
0.78 in19.812 mm
0.79 in20.066 mm
0.8 in20.32 mm
0.81 in20.574 mm
0.82 in20.828 mm
0.83 in21.082 mm
0.84 in21.336 mm
0.85 in21.59 mm
0.86 in21.844 mm
0.87 in22.098 mm
0.88 in22.352 mm
0.89 in22.606 mm
0.9 in22.86 mm
0.91 in23.114 mm
0.92 in23.368 mm
0.93 in23.622 mm
0.94 in23.876 mm
0.95 in24.13 mm
0.96 in24.384 mm
0.97 in24.638 mm
0.98 in24.892 mm
0.99 in25.146 mm
1 in25.4 mm
Inches (in)Millimeters (mm)
1.01 in25.654 mm
1.02 in25.908 mm
1.03 in26.162 mm
1.04 in26.416 mm
1.05 in26.67 mm
1.06 in26.924 mm
1.07 in27.178 mm
1.08 in27.432 mm
1.09 in27.686 mm
1.1 in27.94 mm
1.11 in28.194 mm
1.12 in28.448 mm
1.13 in28.702 mm
1.14 in28.956 mm
1.15 in29.21 mm
1.16 in29.464 mm
1.17 in29.718 mm
1.18 in29.972 mm
1.19 in30.226 mm
1.2 in30.48 mm
1.21 in30.734 mm
1.22 in30.988 mm
1.23 in31.242 mm
1.24 in31.496 mm
1.25 in31.75 mm
1.26 in32.004 mm
1.27 in32.258 mm
1.28 in32.512 mm
1.29 in32.766 mm
1.3 in33.02 mm
1.31 in33.274 mm
1.32 in33.528 mm
1.33 in33.782 mm
1.34 in34.036 mm
1.35 in34.29 mm
1.36 in34.544 mm
1.37 in34.798 mm
1.38 in35.052 mm
1.39 in35.306 mm
1.4 in35.56 mm
1.41 in35.814 mm
1.42 in36.068 mm
1.43 in36.322 mm
1.44 in36.576 mm
1.45 in36.83 mm
1.46 in37.084 mm
1.47 in37.338 mm
1.48 in37.592 mm
1.49 in37.846 mm
1.5 in38.1 mm

Frequently asked questions

How many mm is an inch?

Answer: Converting an inch to millimeters gives 25.4 mm. This comes from the standard conversion factor of 1 inch = 25.4 millimeters.

Calculation: 1 in × 25.4 mm/in = 25.4 mm

What is an inch in other imperial units?

Answer: You can also express an inch as:

  • 0.083333 feet (ft)
  • 0.000016 miles (mi)

What is 1 mm in inches?

Answer: To convert millimeters to inches, use the reverse factor.

Calculation: 1 mm ÷ 25.4 in/mm = 0.03937 in