Workshop reference

Fraction, Decimal, and Millimeter Chart

Common inch fractions from 1/64 through 1 inch with decimal and millimeter equivalents.

FractionDecimal inchMillimeters
1/640.0156250.3969
1/320.0312500.7937
3/640.0468751.1906
1/160.0625001.5875
5/640.0781251.9844
3/320.0937502.3812
7/640.1093752.7781
1/80.1250003.1750
9/640.1406253.5719
5/320.1562503.9688
11/640.1718754.3656
3/160.1875004.7625
13/640.2031255.1594
7/320.2187505.5562
15/640.2343755.9531
1/40.2500006.3500
17/640.2656256.7469
9/320.2812507.1437
19/640.2968757.5406
5/160.3125007.9375
21/640.3281258.3344
11/320.3437508.7312
23/640.3593759.1281
3/80.3750009.5250
25/640.3906259.9219
13/320.40625010.3187
27/640.42187510.7156
7/160.43750011.1125
29/640.45312511.5094
15/320.46875011.9062
31/640.48437512.3031
1/20.50000012.7000
33/640.51562513.0969
17/320.53125013.4937
35/640.54687513.8906
9/160.56250014.2875
37/640.57812514.6844
19/320.59375015.0812
39/640.60937515.4781
5/80.62500015.8750
41/640.64062516.2719
21/320.65625016.6687
43/640.67187517.0656
11/160.68750017.4625
45/640.70312517.8594
23/320.71875018.2562
47/640.73437518.6531
3/40.75000019.0500
49/640.76562519.4469
25/320.78125019.8438
51/640.79687520.2406
13/160.81250020.6375
53/640.82812521.0344
27/320.84375021.4312
55/640.85937521.8281
7/80.87500022.2250
57/640.89062522.6219
29/320.90625023.0187
59/640.92187523.4156
15/160.93750023.8125
61/640.95312524.2094
31/320.96875024.6062
63/640.98437525.0031
11.00000025.4000
Goldie making a reminder note

Use the chart as a starting point

Reference values help compare sizes and plan a job. Product specifications, codes, tolerances, and the actual material still control the final choice.