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ASdrawn

Decimal equivalents

17/64 in is 0.265625 in, 6.747 mm; 0.266 in is nearest 17/64 on a 64ths rule. Type a size however it is written (a fraction, a decimal inch, millimetres, a number or a letter drill) for its decimal inch, millimetres, the nearest fraction on a 1/64, 1/32, 1/16 or 1/8 scale and the drills either side.

The size is drawn on a steel rule’s inch, and the chart of every drill to 1 in prints on one page for the wall.

A bare number is in
Nearest
Decimal inch
Nearest 1/64
Millimetres
Drill at this size
17/64 in
Inch drills either side
G 0.2610 · H 0.2660
Metric drills either side
6.7 mm · 6.8 mm
How it’s calculated

exactly, and the nearest fraction is n/64 with n = round(64 × in), reduced. Here: 0.265625 × 25.4 = 6.747 mm; n = round(64 × 0.265625) = 17, so 17/64 in.

SizeSeriesinmm
#80Number0.01350.343
#79Number0.01450.368
1/64Fraction0.0156250.397
#78Number0.01600.406
#77Number0.01800.457
#76Number0.02000.508
#75Number0.02100.533
#74Number0.02250.571
#73Number0.02400.610
#72Number0.02500.635
#71Number0.02600.660
#70Number0.02800.711
#69Number0.02920.742
#68Number0.03100.787
1/32Fraction0.031250.794
#67Number0.03200.813
#66Number0.03300.838
#65Number0.03500.889
#64Number0.03600.914
#63Number0.03700.940
#62Number0.03800.965
#61Number0.03900.991
1.0Metric0.03941.000
#60Number0.04001.016
#59Number0.04101.041
#58Number0.04201.067
#57Number0.04301.092
1.1Metric0.04331.100
#56Number0.04651.181
3/64Fraction0.0468751.191
1.2Metric0.04721.200
1.3Metric0.05121.300
#55Number0.05201.321
#54Number0.05501.397
1.4Metric0.05511.400
1.5Metric0.05911.500
#53Number0.05951.511
1/16Fraction0.06251.587
1.6Metric0.06301.600
#52Number0.06351.613
1.7Metric0.06691.700
#51Number0.06701.702
#50Number0.07001.778
1.8Metric0.07091.800
#49Number0.07301.854
1.9Metric0.07481.900
#48Number0.07601.930
5/64Fraction0.0781251.984
#47Number0.07851.994
2.0Metric0.07872.000
#46Number0.08102.057
#45Number0.08202.083
2.1Metric0.08272.100
#44Number0.08602.184
2.2Metric0.08662.200
#43Number0.08902.261
2.3Metric0.09062.300
#42Number0.09352.375
3/32Fraction0.093752.381
2.4Metric0.09452.400
#41Number0.09602.438
#40Number0.09802.489
2.5Metric0.09842.500
#39Number0.09952.527
#38Number0.10152.578
2.6Metric0.10242.600
#37Number0.10402.642
2.7Metric0.10632.700
#36Number0.10652.705
7/64Fraction0.1093752.778
#35Number0.11002.794
2.8Metric0.11022.800
#34Number0.11102.819
#33Number0.11302.870
2.9Metric0.11422.900
#32Number0.11602.946
3.0Metric0.11813.000
#31Number0.12003.048
3.1Metric0.12203.100
1/8Fraction0.12503.175
3.2Metric0.12603.200
#30Number0.12853.264
3.3Metric0.12993.300
3.4Metric0.13393.400
#29Number0.13603.454
3.5Metric0.13783.500
#28Number0.14053.569
9/64Fraction0.1406253.572
3.6Metric0.14173.600
#27Number0.14403.658
3.7Metric0.14573.700
#26Number0.14703.734
#25Number0.14953.797
3.8Metric0.14963.800
#24Number0.15203.861
3.9Metric0.15353.900
#23Number0.15403.912
5/32Fraction0.156253.969
#22Number0.15703.988
4.0Metric0.15754.000
#21Number0.15904.039
#20Number0.16104.089
4.1Metric0.16144.100
4.2Metric0.16544.200
#19Number0.16604.216
4.3Metric0.16934.300
#18Number0.16954.305
11/64Fraction0.1718754.366
#17Number0.17304.394
4.4Metric0.17324.400
#16Number0.17704.496
4.5Metric0.17724.500
#15Number0.18004.572
4.6Metric0.18114.600
#14Number0.18204.623
#13Number0.18504.699
4.7Metric0.18504.700
3/16Fraction0.18754.762
4.8Metric0.18904.800
#12Number0.18904.801
#11Number0.19104.851
4.9Metric0.19294.900
#10Number0.19354.915
#9Number0.19604.978
5.0Metric0.19695.000
#8Number0.19905.055
5.1Metric0.20085.100
#7Number0.20105.105
13/64Fraction0.2031255.159
#6Number0.20405.182
5.2Metric0.20475.200
#5Number0.20555.220
5.3Metric0.20875.300
#4Number0.20905.309
5.4Metric0.21265.400
#3Number0.21305.410
5.5Metric0.21655.500
7/32Fraction0.218755.556
5.6Metric0.22055.600
#2Number0.22105.613
5.7Metric0.22445.700
#1Number0.22805.791
5.8Metric0.22835.800
5.9Metric0.23235.900
ALetter0.23405.944
15/64Fraction0.2343755.953
6.0Metric0.23626.000
BLetter0.23806.045
6.1Metric0.24026.100
CLetter0.24206.147
6.2Metric0.24416.200
DLetter0.24606.248
6.3Metric0.24806.300
ELetter0.25006.350
1/4Fraction0.25006.350
6.4Metric0.25206.400
6.5Metric0.25596.500
FLetter0.25706.528
6.6Metric0.25986.600
GLetter0.26106.629
6.7Metric0.26386.700
17/64Fraction0.2656256.747
HLetter0.26606.756
6.8Metric0.26776.800
6.9Metric0.27176.900
ILetter0.27206.909
7.0Metric0.27567.000
JLetter0.27707.036
7.1Metric0.27957.100
KLetter0.28107.137
9/32Fraction0.281257.144
7.2Metric0.28357.200
7.3Metric0.28747.300
LLetter0.29007.366
7.4Metric0.29137.400
MLetter0.29507.493
7.5Metric0.29537.500
19/64Fraction0.2968757.541
7.6Metric0.29927.600
NLetter0.30207.671
7.7Metric0.30317.700
7.8Metric0.30717.800
7.9Metric0.31107.900
5/16Fraction0.31257.938
8.0Metric0.31508.000
OLetter0.31608.026
8.1Metric0.31898.100
8.2Metric0.32288.200
PLetter0.32308.204
8.3Metric0.32688.300
21/64Fraction0.3281258.334
8.4Metric0.33078.400
QLetter0.33208.433
8.5Metric0.33468.500
8.6Metric0.33868.600
RLetter0.33908.611
8.7Metric0.34258.700
11/32Fraction0.343758.731
8.8Metric0.34658.800
SLetter0.34808.839
8.9Metric0.35048.900
9.0Metric0.35439.000
TLetter0.35809.093
9.1Metric0.35839.100
23/64Fraction0.3593759.128
9.2Metric0.36229.200
9.3Metric0.36619.300
ULetter0.36809.347
9.4Metric0.37019.400
9.5Metric0.37409.500
3/8Fraction0.37509.525
VLetter0.37709.576
9.6Metric0.37809.600
9.7Metric0.38199.700
9.8Metric0.38589.800
WLetter0.38609.804
9.9Metric0.38989.900
25/64Fraction0.3906259.922
10.0Metric0.393710.000
XLetter0.397010.084
10.1Metric0.397610.100
10.2Metric0.401610.200
YLetter0.404010.262
10.3Metric0.405510.300
13/32Fraction0.4062510.319
10.4Metric0.409410.400
ZLetter0.413010.490
10.5Metric0.413410.500
10.6Metric0.417310.600
10.7Metric0.421310.700
27/64Fraction0.42187510.716
10.8Metric0.425210.800
10.9Metric0.429110.900
11.0Metric0.433111.000
11.1Metric0.437011.100
7/16Fraction0.437511.112
11.2Metric0.440911.200
11.3Metric0.444911.300
11.4Metric0.448811.400
11.5Metric0.452811.500
29/64Fraction0.45312511.509
11.6Metric0.456711.600
11.7Metric0.460611.700
11.8Metric0.464611.800
11.9Metric0.468511.900
15/32Fraction0.4687511.906
12.0Metric0.472412.000
12.1Metric0.476412.100
12.2Metric0.480312.200
12.3Metric0.484312.300
31/64Fraction0.48437512.303
12.4Metric0.488212.400
12.5Metric0.492112.500
12.6Metric0.496112.600
1/2Fraction0.500012.700
12.7Metric0.500012.700
12.8Metric0.503912.800
12.9Metric0.507912.900
13.0Metric0.511813.000
33/64Fraction0.51562513.097
13.1Metric0.515713.100
13.2Metric0.519713.200
13.3Metric0.523613.300
13.4Metric0.527613.400
17/32Fraction0.5312513.494
13.5Metric0.531513.500
13.6Metric0.535413.600
13.7Metric0.539413.700
13.8Metric0.543313.800
35/64Fraction0.54687513.891
13.9Metric0.547213.900
14.0Metric0.551214.000
14.25Metric0.561014.250
9/16Fraction0.562514.287
14.5Metric0.570914.500
37/64Fraction0.57812514.684
14.75Metric0.580714.750
15.0Metric0.590615.000
19/32Fraction0.5937515.081
15.25Metric0.600415.250
39/64Fraction0.60937515.478
15.5Metric0.610215.500
15.75Metric0.620115.750
5/8Fraction0.625015.875
16.0Metric0.629916.000
41/64Fraction0.64062516.272
16.5Metric0.649616.500
21/32Fraction0.6562516.669
17.0Metric0.669317.000
43/64Fraction0.67187517.066
11/16Fraction0.687517.462
17.5Metric0.689017.500
45/64Fraction0.70312517.859
18.0Metric0.708718.000
23/32Fraction0.7187518.256
18.5Metric0.728318.500
47/64Fraction0.73437518.653
19.0Metric0.748019.000
3/4Fraction0.750019.050
49/64Fraction0.76562519.447
19.5Metric0.767719.500
25/32Fraction0.7812519.844
20.0Metric0.787420.000
51/64Fraction0.79687520.241
20.5Metric0.807120.500
13/16Fraction0.812520.637
21.0Metric0.826821.000
53/64Fraction0.82812521.034
27/32Fraction0.8437521.431
21.5Metric0.846521.500
55/64Fraction0.85937521.828
22.0Metric0.866122.000
7/8Fraction0.875022.225
22.5Metric0.885822.500
57/64Fraction0.89062522.622
23.0Metric0.905523.000
29/32Fraction0.9062523.019
59/64Fraction0.92187523.416
23.5Metric0.925223.500
15/16Fraction0.937523.813
24.0Metric0.944924.000
61/64Fraction0.95312524.209
24.5Metric0.964624.500
31/32Fraction0.9687524.606
25.0Metric0.984325.000
63/64Fraction0.98437525.003
1Fraction1.000025.400

Why does a decimal chart list drills as well as fractions?

Number and letter drills fill the gaps between the 64ths: a #7 drill (0.2010 in) sits between 3/16 and 13/64, which is why a tap drill is often a number or a letter rather than a fraction. Reading the chart by size, smallest first, shows every drill within a few thousandths of the size you need, inch and metric together.