Fraction to Metric Conversion Chart

Quick reference for converting imperial fractions (1/64" increments) to decimal inches and millimeters. Useful for woodworking, metalworking, and general measurements.

FractionCommon1/41/81/161/321/64DecimalMillimeters
1/641/640.0156250.396875
1/321/320.031250.79375
3/643/640.0468751.190625
1/161/160.06251.5875
5/645/640.0781251.984375
3/323/320.093752.38125
7/647/640.1093752.778125
1/81/80.1253.175
9/649/640.1406253.571875
5/325/320.156253.96875
11/6411/640.1718754.365625
3/163/160.18754.7625
13/6413/640.2031255.159375
7/327/320.218755.55625
15/6415/640.2343755.953125
1/41/40.256.35
17/6417/640.2656256.746875
9/329/320.281257.14375
19/6419/640.2968757.540625
5/165/160.31257.9375
21/6421/640.3281258.334375
11/3211/320.343758.73125
23/6423/640.3593759.128125
3/83/80.3759.525
25/6425/640.3906259.921875
13/3213/320.4062510.31875
27/6427/640.42187510.715625
7/167/160.437511.1125
29/6429/640.45312511.509375
15/3215/320.4687511.90625
31/6431/640.48437512.303125
1/21/20.512.7
33/6433/640.51562513.096875
17/3217/320.5312513.49375
35/6435/640.54687513.890625
9/169/160.562514.2875
37/6437/640.57812514.684375
19/3219/320.5937515.08125
39/6439/640.60937515.478125
5/85/80.62515.875
41/6441/640.64062516.271875
21/3221/320.6562516.66875
43/6443/640.67187517.065625
11/1611/160.687517.4625
45/6445/640.70312517.859375
23/3223/320.7187518.25625
47/6447/640.73437518.653125
3/43/40.7519.05
49/6449/640.76562519.446875
25/3225/320.7812519.84375
51/6451/640.79687520.240625
13/1613/160.812520.6375
53/6453/640.82812521.034375
27/3227/320.8437521.43125
55/6455/640.85937521.828125
7/87/80.87522.225
57/6457/640.89062522.621875
29/3229/320.9062523.01875
59/6459/640.92187523.415625
15/1615/160.937523.8125
61/6461/640.95312524.209375
31/3231/320.9687524.60625
63/6463/640.98437525.003125
1/11/1125.4

How to use this chart:

  • Fraction: The simplified fraction form
  • Common/1/4/1/8/etc: Shows only fractions with that denominator
  • Decimal: Decimal inches (e.g., 0.5 = 1/2 inch)
  • Millimeters: Metric equivalent (1 inch = 25.4mm)
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