Inch & Metric Tap Drill Sizes & Decimal Equivalent Table
Drill sizes are for cutting taps at approximately 75% of thread engagement, excluding pipe threads.
Inch Tap Drill Sizes
Drill
Inch
Inch
Decimal
Tap
Size
#80.0135
#79.0145
1/64.01563
#78.016
#77.018
#76.020
#75.021
#74.0225
#73.024
#72.025
#71.026
#70.028
#69.0292
#68.031
1/32.03125
#67.032
#66.033
#65.035
#64.036
#63.037
#62.038
#61.039
#60.040
#59.041
#58.042
#57.043
#56.0465
3/64.04688#0-80
#55.052
#54.055
#53.0595#1-64
#53.0595#1-72
1/16.0625
#52.0635
#51.067#2-56
#50.070#2-64
#49.073
#48.076
5/64.07813
#47.0785#3-48
#46.081
#45.082#3-56
#44.086
#43.089#4-40
#42.0935#4-48
3/32.09375
#41.096
#40.098
#39.0995
#38.1015#5-40
#37.104#5-44
#36.1065#6-32
7/64.10938
#35.110
#34.111
#33.113#6-40
#32.116
#31.120
Drill
Inch
Inch
Decimal
Tap
Size
1/8.125
#30.1285
#29.136#8-32
#29.136#8-36
#28.1405
9/64.14063
#27.144
#26.147
#25.1495#10-24
#24.152
#23.154
5/32.15625
#22.157
#21.159#10-32
#20.161
#19.166
#18.1695
11/64.17188
#17.173#12-24
#16.177
#15.180#12-28
#14.182
#13.185
3/16.1875
#12.189
#11.191
#10.1935
#9.196
#8.199
#7.2011/4-20
13/64.20313
#6.204
#5.2055
#4.209
#3.2131/4-28
7/32.21875
#2.221
#1.228
A.234
15/64.23438
B.238
C.242
D.246
1/4.250
E.250
F.2575/16-18
G.261
17/64.26563
H.266
I.2725/16-24
J.277
K.281
9/32.28125
L.29
M.295
19/64.29688
N.302
Drill
Inch
Inch
Decimal
Tap
Size
5/16.31253/8-16
O.316
P.323
21/64.32813
Q.3323/8-24
R.339
11/32.34375
S.348
T.3587/16-14
23/64.35938
U.368
3/8.375
V.377
W.386
25/64.390637/16-20
X.397
Y.404
13/32.40625
Z.413
27/64.421881/2-13
7/16.4375
29/64.453131/2-20
15/32.46875
31/64.484389/16-12
1/2.500
33/64.515639/16-18
17/32.531255/8-11
35/64.54688
9/16.56255/8-18
37/64.57813
19/32.59375
39/64.60938
5/8.625
41/64.640633/4-10
21/32.65625
43/64.67188
11/16.68753/4-16
45/64.70313
23/32.71875
47/64.73438
3/4.750
49/64.765637/8-9
25/32.78125
51/64.79688
13/16.81257/8-14
53/64.82813
27/32.84375
55/64.85938
7/8.8751-8
57/64.89063
29/32.906251-12
59/64.92188
15/16.9375
61/64.95313
31/32.96875
63/64.984381 1/8-7
11.000
Metric Tap Drill Sizes
Drill
mm
Inch
Decimal
Tap
Size
0.75.02951x0.25
0.85.03351.1x0.25
0.95.03741.2x0.25
1.10.04331.4x0.30
1.25.04921.6x0.35
1.45.05711.8x0.35
1.6.06302x0.40
1.75.06892x0.25
1.75.06892.2x0.45
1.95.07682.2x0.25
2.05.08072.3x0.25
2.05.08072.5x0.45
2.15.08462.5x0.35
2.5.09843x0.50
2.65.10433x0.35
2.9.11423.5x0.6
3.15.12403.5x0.35
3.3.12994x0.7
3.5.13784x0.5
3.6.14174x0.35
3.7.14574.5x0.75
4.2.16545x0.8
4.5.17725x0.5
5.19696x1
5.25.20676x0.75
5.5.21656x0.5
6.23627x1
Drill
mm
Inch
Decimal
Tap
Size
6.25.24617x0.75
6.8.26778x1.25
7.0.27568x1
7.25.28548x0.75
7.5.29538x0.5
7.8.30719x1.25
8.31509x1
8.2.32289x0.75
8.5.334610x1.5
8.8.346510x1.25
9.354310x1
9.25.364210x0.75
9.5.374010x0.5
9.5.374011x1.5
10.393711x1
10.2.401612x1.75
10.5.413412x1.5
10.8.425212x1.25
11.433112x1
11.25.442912x.75
12.472413x1
12.472414x2
12.5.492114x1.5
12.8.503914x1.25
13.511814x1
13.5.531515x1.5
14.551215x1
Drill
mm
Inch
Decimal
Tap
Size
14.551216x2
14.5.570916x1.5
15.590616x1
15.5.610218x2.5
16.629918x2
16.5.649618x1.5
17.669318x1
17.5.689020x2.5
18.708720x2
18.5.728320x1.5
19.748020x1
19.5.767722x2.5
20.787422x2
20.5.807122x1.5
21.826822x1
21.826824x3
22.866124x2
22.5.885824x1.5
23.905524x1
23.5.925225x1.5
24.94495x1
24.944927x3
24.5.964626x1.5
25.984327x2
25.51.003927x1.5
261.023628x2
26.51.043328x1.5
Pipe Tap Drill Sizes in Inches
Drill NPTDrill NPSTap Size
D1/41/16-27
RS1/8-27
7/1629/641/4-18
37/6419/323/8-18
Drill NPTDrill NPSTap Size
45/6447/641/2-14
59/6415/163/4-14
1 5/321 3/161-11.5
1 1/21 33/641.25-11.5
Drill NPTDrill NPSTap Size
1 47/641 3/41.5-11.5
2 7/322 7/322-11.5
2 5/82 21/322.5-8
3 1/43 9/323-8

Note: Great care has been made to make sure this information is accurate. However, due to human error, the user agrees to accept full responsibility to verify that the provided information meets their requirements before using it.