Unit Converter

Convert between fractions, decimal inches, and millimeters

Convert

Reference Table — 1/64" to 1"

FractionDecimal (in)Millimeters
1/64"0.01560.3969
1/32"0.03130.7938
3/64"0.04691.1906
1/16"0.06251.5875
5/64"0.07811.9844
3/32"0.09382.3812
7/64"0.10942.7781
1/8"0.12503.1750
9/64"0.14063.5719
5/32"0.15633.9688
11/64"0.17194.3656
3/16"0.18754.7625
13/64"0.20315.1594
7/32"0.21885.5562
15/64"0.23445.9531
1/4"0.25006.3500
17/64"0.26566.7469
9/32"0.28137.1438
19/64"0.29697.5406
5/16"0.31257.9375
21/64"0.32818.3344
11/32"0.34388.7313
23/64"0.35949.1281
3/8"0.37509.5250
25/64"0.39069.9219
13/32"0.406310.3188
27/64"0.421910.7156
7/16"0.437511.1125
29/64"0.453111.5094
15/32"0.468811.9063
31/64"0.484412.3031
1/2"0.500012.7000
33/64"0.515613.0969
17/32"0.531313.4938
35/64"0.546913.8906
9/16"0.562514.2875
37/64"0.578114.6844
19/32"0.593815.0813
39/64"0.609415.4781
5/8"0.625015.8750
41/64"0.640616.2719
21/32"0.656316.6688
43/64"0.671917.0656
11/16"0.687517.4625
45/64"0.703117.8594
23/32"0.718818.2562
47/64"0.734418.6531
3/4"0.750019.0500
49/64"0.765619.4469
25/32"0.781319.8438
51/64"0.796920.2406
13/16"0.812520.6375
53/64"0.828121.0344
27/32"0.843821.4313
55/64"0.859421.8281
7/8"0.875022.2250
57/64"0.890622.6219
29/32"0.906323.0187
59/64"0.921923.4156
15/16"0.937523.8125
61/64"0.953124.2094
31/32"0.968824.6063
63/64"0.984425.0031
1"1.000025.4000

How to Convert Between Fractions, Decimals, and Millimeters

Machinists regularly need to convert between fractional inches, decimal inches, and millimeters. This converter handles all three formats instantly — type in any field and the other two update automatically.

Fraction to Decimal

Divide the numerator by the denominator. For example, 3/8 = 0.375". This converter finds the closest standard fraction (up to 64ths) for any decimal value.

Inches to Millimeters

Multiply inches by 25.4. For example, 0.375" × 25.4 = 9.525 mm.

Millimeters to Inches

Divide millimeters by 25.4. For example, 9.525 mm ÷ 25.4 = 0.375".

Common Uses

This tool is essential when working with prints that mix imperial and metric dimensions, selecting drill bits, verifying caliper readings, or converting between measurement systems for material ordering.