Inches to Millimeters (in to mm)

/

mm to inches (Swap Units)

Format
Accuracy

Note: Fractional results are rounded to the nearest 1/64. For a more accurate answer please select 'decimal' from the options above the result.

Note: You can increase or decrease the accuracy of this answer by selecting the number of significant figures required from the options above the result.

Note: For a pure decimal result please select 'decimal' from the options above the result.

Show formula

Inches to Millimeters formula

mm =
in
 
________
 
 
0.039370
Show working
Show result in exponential format
More information: Inches
More information: Millimeters

Inches

Use of the inch can be traced back as far as the 7th century. The first explicit definition we could find of its length was after 1066 when it was defined as the length of three barleycorns. This was not a satisfactory reference as barleycorn lengths vary naturally. The British Standards Institute defined the inch as 25.4mm in 1930 in the document "Metric Units in Engineering: Going SI". In March 1932 the American Standards Association were asked to rule on whether to adopt the same value (at the time the American inch was 1/.03937 mm which approximated to 25.400051 mm). Because the values were so close, and because Britain has already settled on that value, the ASA adopted this value on March 13, 1933.

 

Inches to Millimeters formula

mm =
in
 
________
 
 
0.039370

Millimeters

The millimetre is a unit of length in the metric system, equivalent to one thousandth of a metre (the SI base unit of length).

One meter was defined in 1983 by the 17th conference of weights and measures as “the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second” and the millimetre by definition is derived as being 1/1000th of that value.

 

Inches to Millimeters table

Start
Increments
Accuracy
Format
Print table
< Smaller Values Larger Values >
-20.000in-508.00mm
-19.000in-482.60mm
-18.000in-457.20mm
-17.000in-431.80mm
-16.000in-406.40mm
-15.000in-381.00mm
-14.000in-355.60mm
-13.000in-330.20mm
-12.000in-304.80mm
-11.000in-279.40mm
-10.000in-254.00mm
-9.0000in-228.60mm
-8.0000in-203.20mm
-7.0000in-177.80mm
-6.0000in-152.40mm
-5.0000in-127.00mm
-4.0000in-101.60mm
-3.0000in-76.200mm
-2.0000in-50.800mm
-1.0000in-25.400mm
Inches Millimeters
0.0000in 0.0000mm
1.0000in 25.400mm
2.0000in 50.800mm
3.0000in 76.200mm
4.0000in 101.60mm
5.0000in 127.00mm
6.0000in 152.40mm
7.0000in 177.80mm
8.0000in 203.20mm
9.0000in 228.60mm
10.000in 254.00mm
11.000in 279.40mm
12.000in 304.80mm
13.000in 330.20mm
14.000in 355.60mm
15.000in 381.00mm
16.000in 406.40mm
17.000in 431.80mm
18.000in 457.20mm
19.000in 482.60mm
Inches Millimeters
20.000in 508.00mm
21.000in 533.40mm
22.000in 558.80mm
23.000in 584.20mm
24.000in 609.60mm
25.000in 635.00mm
26.000in 660.40mm
27.000in 685.80mm
28.000in 711.20mm
29.000in 736.60mm
30.000in 762.00mm
31.000in 787.40mm
32.000in 812.80mm
33.000in 838.20mm
34.000in 863.60mm
35.000in 889.00mm
36.000in 914.40mm
37.000in 939.80mm
38.000in 965.20mm
39.000in 990.60mm
Inches Millimeters
40.000in 1016.0mm
41.000in 1041.4mm
42.000in 1066.8mm
43.000in 1092.2mm
44.000in 1117.6mm
45.000in 1143.0mm
46.000in 1168.4mm
47.000in 1193.8mm
48.000in 1219.2mm
49.000in 1244.6mm
50.000in 1270.0mm
51.000in 1295.4mm
52.000in 1320.8mm
53.000in 1346.2mm
54.000in 1371.6mm
55.000in 1397.0mm
56.000in 1422.4mm
57.000in 1447.8mm
58.000in 1473.2mm
59.000in 1498.6mm
60.000in1524.0mm
61.000in1549.4mm
62.000in1574.8mm
63.000in1600.2mm
64.000in1625.6mm
65.000in1651.0mm
66.000in1676.4mm
67.000in1701.8mm
68.000in1727.2mm
69.000in1752.6mm
70.000in1778.0mm
71.000in1803.4mm
72.000in1828.8mm
73.000in1854.2mm
74.000in1879.6mm
75.000in1905.0mm
76.000in1930.4mm
77.000in1955.8mm
78.000in1981.2mm
79.000in2006.6mm