Drill Bit Size Chart
Page 1 of 7
Drill sizes to 1" diameter
Legend
Fractional Inch
Letter Drill
Millimeters
Number Drill
Designation
Tap Drill/Pilot Drill Uses
#80
#79
1/64"
#0 Pilot, Soft-Wood
#78
#77
Millimeters
.3429mm
.3683mm
.3969mm
.4064mm
.4572mm
.5mm
.508mm
.5334mm
.5715mm
.6096mm
.635mm
.6604mm
.7112mm
.74168mm
.75mm
.7874mm
Inches
.0135"
.0145"
.015625"
.016"
.018"
.0197"
.02"
.021"
.0225"
.024"
.025"
.026"
.028"
.0292"
.0295"
.031"
.7938mm
.03125"
1/32"
.8128mm
.8382mm
.85mm
.889mm
.9144mm
.9398mm
.95mm
.9652mm
.9906mm
1mm
1.016mm
1.0414mm
1.0668mm
1.0922mm
1.1mm
.032"
.033"
.0335"
.035"
.036"
.037"
.0374"
.038"
.039"
.0394"
.04"
.041"
.042"
.043"
.0433"
#67
#66
#76
#75
#74
#73
#72
#71
#70
#69
M1x.25 coarse
#68
#0 Pilot, Hard-Wood #1 Pilot, Hard & SoftWood #2 Pilot, Soft-Wood
M1.1x.25 coarse
#65
#64
#63
M1.2x.25 coarse
#62
#61
#60
#59
#58
#57
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M1.4x.3 coarse
03/06/2011
Drill Bit Size Chart
Page 2 of 7
1.1811mm
.0465"
#56
1.1906mm
.046875"
3/64"
1.25mm
1.3mm
1.3208mm
1.397mm
1.45mm
1.5mm
1.5113mm
.0492"
.0512"
.052"
.055"
.0571"
.0591"
.0595"
1.5875mm
.0625"
1.6mm
1.6129mm
1.7018mm
1.75mm
1.778mm
1.8542mm
1.9304mm
.063"
.0635"
.067"
.0689"
.07"
.073"
.076"
1.9844mm
.078125"
5/64"
1.9939mm
2mm
2.05mm
2.0574mm
2.0828mm
2.1844mm
2.2606mm
2.3749mm
.0785"
.0787"
.0807"
.081"
.082"
.086"
.089"
.0935"
#47
2.3813mm
.09375"
3/32"
2.4384mm
2.4892mm
2.5mm
2.5273mm
2.5781mm
2.6416mm
2.7051mm
.096"
.098"
.0984"
.0995"
.1015"
.104"
.1065"
#41
#40
#0-80 UNF#2 Pilot, Hard-wood, #3 Pilot,
Soft-Wood #4 Pilot, Soft-Wood
M1.6x.35 coarse
M1.7x.35 coarse
#55
#54
M1.8x.35 coarse
#53
1/16"
#1-64 UNC, #1-72 UNF
#0 Wood Shank Hole, #3 Pilot, Hard-Wood,
#4 Pilot, Hard-wood #5 Pilot, Soft-wood, #6
Pilot, Soft-wood, #7 Pilot, Soft-wood
M2x.4 coarse
#52
#51
#50
#49
#48
M2.2x.45 coarse
#2-64 UNF, #2-56 UNC
#1 Wood Shank Hole#5 Pilot, Hard-wood,
#6 Pilot, Hard-wood #8 Pilot, Soft-wood, #9
Pilot, Soft-wood
#3-48 UNC
M2.5x.45 coarse
#46
#45
#44
#43
#42
#3-56 UNF
#4-40 UNC
#4-48 UNF
#2 Wood Shank Hole, #7 Pilot, Hard-wood,
#8 Pilot, Hard-wood, #10 Pilot, Soft-wood,
#11 Pilot, Soft-wood
M3x.5 coarse
#39
#38
#37
#36
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#5-40 UNC
#5-44 UNF
#6-32 UNC
03/06/2011
Drill Bit Size Chart
Page 3 of 7
2.7781mm
.109375"
7/64"
2.794mm
2.8194mm
2.8702mm
2.9mm
2.9464mm
3mm
3.048mm
.11"
.111"
.113"
.1142"
.116"
.1181"
.12"
#35
#34
#33
3.175mm
.125"
1/8"
3.2639mm
3.3mm
3.4544mm
3.5mm
3.5687mm
.1285"
.1299"
.136"
.1378"
.1405"
#30
3.5719mm
.140625"
3.6mm
3.6576mm
3.7mm
3.7338mm
3.7973mm
3.8608mm
3.9116mm
3.9688mm
3.9878mm
4mm
4.0386mm
4.0894mm
4.2mm
4.2164mm
4.3053mm
4.3656mm
4.3942mm
4.4958mm
4.5mm
4.572mm
.1417"
.144"
.1457"
.147"
.1495"
.152"
.154"
.15625"
.157"
.1575"
.159"
.161"
.1654"
.166"
.1695"
.171875"
.173"
.177"
.1772"
.18"
#3 Wood Shank Hole, #4 Wood Shank
Hole, #9 Pilot, Hard-wood #10 Pilot, Hardwood, #12 Pilot, Soft-wood, #14 Pilot, Softwood
#6-40 UNF
M3.5x.6 coarse
#32
#31
#29
#5 Wood Shank Hole, #11 Pilot, Hardwood, #12 Pilot, Hard-wood
M4x.7 coarse
#8-32 UNC, #8-36 UNF
M4x.5 Fine
#28
9/64"
#6 Wood Shank Hole, #14 Pilot, Hardwood, #16 Pilot, Soft-wood #18 Pilot, Softwood
M4x.35 Fine
#27
M4.5x.75 coarse
#26
#25
#24
#23
5/32"
#22
#21
#20
#10-24 UNC
#7 Wood Shank Hole, #16 Pilot, Hard-wood
#10-32 UNF
M5x.8 coarse
#19
#18
11/64"
#17
#16
#15
http://bobmay.astronomy.net/misc/drillchart.htm
#8 Wood Shank Hole, #20 Pilot, Soft-wood
#12-24 UNC
M5x.5 Fine
#12-28 UNF
03/06/2011
Drill Bit Size Chart
Page 4 of 7
4.6228mm
4.699mm
.182"
.185"
#14
#13
4.7625mm
.1875"
3/16"
4.8006mm
4.8514mm
4.9149mm
4.9784mm
5mm
5.0546mm
5.1054mm
.189"
.191"
.1935"
.196"
.1969"
.199"
.201"
#12
#11
#10
#9
5.1594mm
.203125"
13/64"
5.1816mm
5.2197mm
5.25mm
5.3086mm
5.4102mm
5.5mm
5.5563mm
5.6134mm
5.7912mm
5.9436mm
5.9531mm
6mm
6.0452mm
6.1468mm
6.2484mm
6.25mm
6.35mm
6.35mm
6.5mm
6.5278mm
6.6294mm
6.7469mm
6.7564mm
6.8mm
6.9088mm
7mm
7.0358mm
.204"
.2055"
.2067"
.209"
.213"
.2165"
.21875"
.221"
.228"
.234"
.234375"
.2362"
.238"
.242"
.246"
.2461"
.25"
.25"
.2559"
.257"
.261"
.265625"
.266"
.2677"
.272"
.2756"
.277"
#6
#5
#9 Wood Shank Hole, #10 Wood Shank
Hole, #18 Pilot, Hardwood
M6x1 coarse
#8
#7
1/4"-20 UNC
#11 Wood Shank Hole, #20 Pilot, Hardwood
M6x.75 Fine
#4
#3
7/32"
#2
#1
A
15/64"
1/4"-28 UNF
M6x.5 Fine
#12 Wood Shank Hole
M7x1 coarse
B
C
D
1/4"
E
F
G
17/64"
H
I
1/16"-27 NPT
M7x.75 Fine
#14 Wood Shank Hole
5/16"-18 UNC
#16 Wood Shank Hole
M8x1.25 coarse
5/16"-24 UNF
M8x.5 Fine
J
http://bobmay.astronomy.net/misc/drillchart.htm
03/06/2011
Drill Bit Size Chart
7.1374mm
7.1438mm
7.25mm
7.366mm
7.493mm
7.5mm
7.5406mm
7.6708mm
7.8mm
7.9375mm
8mm
8.0264mm
8.2042mm
8.3344mm
8.4328mm
8.5mm
8.6106mm
8.7313mm
8.8mm
8.8392mm
9mm
9.0932mm
9.1281mm
9.25mm
9.3472mm
9.5mm
9.525mm
9.5758mm
9.8044mm
9.9219mm
10mm
10.0838mm
10.2mm
10.2616mm
10.3188mm
10.4902mm
10.5mm
10.7156mm
11mm
Page 5 of 7
.281"
.28125"
.2854"
.29"
.295"
.2953"
.296875"
.302"
.3071"
.3125"
.315"
.316"
.323"
.328125"
.332"
.3346"
.339"
.34375"
.3465"
.348"
.3543"
.358"
.359375"
.3642"
.368"
.374"
.375"
.377"
.386"
.390625"
.3937"
.397"
.4016"
.404"
.40625"
.413"
.4134"
.421875"
.4331"
K
9/32"
M8x.75 Fine
L
M
19/64"
N
5/16"
O
P
21/64"
Q
R
11/32"
M8x1 Fine
#18 Wood Shank Hole
M9x1.25 coarse
3/8"-16 UNC
M9x1 Fine
#20 Wood Shank Hole
3/8"-24 UNF
M10x1.5 coarse
1/8"-27 NPT
M10x1.25 Fine
S
T
23/64"
M10x1 Fine
7/16"-14 UNC
M10x.75 Fine
U
M11x1.5 coarse
3/8"
V
W
25/64"
7/16"-20 UNF
M11x1 Fine
X
M12x1.75 coarse
Y
13/32"
Z
27/64"
M12x1.5 Fine
1/2"-13 UNC
M12x1 Fine
11.1125mm
http://bobmay.astronomy.net/misc/drillchart.htm
03/06/2011
Drill Bit Size Chart
11.25mm
11.5mm
11.5094mm
11.9063mm
12mm
12.3031mm
12.5mm
12.7mm
12.8mm
13mm
13.0969mm
13.4938mm
13.5mm
13.8906mm
14mm
14.2875mm
14.5mm
14.6844mm
15mm
15.0813mm
15.4781mm
15.5mm
15.875mm
16mm
16.2719mm
16.5mm
16.6688mm
17mm
17.0656mm
17.4625mm
17.5mm
17.8594mm
18mm
18.2563mm
18.5mm
18.6531mm
19mm
19.05mm
Page 6 of 7
.4375"
.4429"
.4528"
.453125"
.46875"
.4724"
.484375"
.4921"
.5"
.5039"
.5118"
.515625"
.53125"
.5315"
.546875"
.5512"
.5625"
.5709"
.578125"
.5906"
.59375"
.609375"
.6102"
.625"
.6299"
.640625"
.6496"
.65625"
.6693"
.671875"
.6875"
.689"
.703125"
.7087"
.71875"
.7283"
.734375"
.748"
.75"
7/16"
1/4"-18 NPT
M12x.75 Fine
29/64"
15/32"
1/2"-20 UNF
31/64"
M14x2 coarse
9/16"-12 UNC
M14x1.5 Fine
1/2"
33/64"
17/32"
M14x1.25 Fine
M14x1 Fine
9/16"-18 UNF
5/8"-11 UNC
35/64"
9/16"
37/64"
M16x2 coarse
5/8"-18 UNF
M16x1.5 Fine
3/8"-18 NPT
M16x1 Fine
19/32"
39/64"
M18x2.5 coarse
5/8"
41/64"
M18x2 Fine
3/4"-10 UNC
21/32"
M18x1 Fine
43/64"
11/16"
45/64"
3/4"-16 UNF
M20x2.5 coarse
1/2"-14 NPT
M20x2 Fine
23/32"
M20x1.5 Fine
47/64"
M20x1 Fine
3/4"
19.4469mm
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03/06/2011
Drill Bit Size Chart
Page 7 of 7
.765625"
49/64"
7/8"-9 UNC
19.5mm
.7677"
M22x2.5 coarse
19.8438mm
.78125"
25/32"
20mm
.7874"
M22x2 Fine
20.2406mm
.796875"
51/64"
20.5mm
.8071"
M22x1.5 Fine
20.6375mm
.8125"
13/16"
7/8"-14 UNF
21mm
.8268"
M24x3 coarseM22x1 Fine
21.0344mm
.828125"
53/64"
21.4313mm
.84375"
27/32"
21.5mm
.8465"
21.8281mm
.859375"
55/64"
22mm
.8661"
M24x2 Fine
22.225mm
.875"
7/8"
1"-8 UNC
22.5mm
.8858"
M24x1.5 Fine
22.6219mm
.890625"
57/64"
23mm
.9055"
23.0188mm
.90625"
29/32"
1"-12 UNF
23.4156mm
.921875"
59/64"
3/4"-14 NPT
23.5mm
.9252"
23.8125mm
.9375"
15/16"
24mm
.9449"
M27x3 coarse
24.2094mm
.953125"
61/64"
24.5mm
.9646"
M26x1.5 Fine
24.6063mm
.96875"
31/32"
25mm
.9843"
M27x2 Fine
25.0031mm
.984375"
63/64"
1-1/8"-7 UNC
25.4mm
1.000"
1"
When using a drill bit for a feeler gauge, please remember that many drill bits are actually undersize at
the shank end of the drill bit so please use the above bit sizes with a grain of salt!
Also note that to correct for a broad feeler gauge or a loose-fitting drill bit:
ROC = (D
2-W2)
/
8T
Where:
W = the width of the feeler gauge, or if the drill bit can be moved back and forth under the straight
edge by the total amount W
D = mirror diameter,
T = gauge thickness or bit diameter.
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03/06/2011