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Online Tools >> Drill Size Conversion

Drill Size ConversionS

This is the place to easily gauge conversion factors for common drill and tap sizes. You may use the conversion calculator to determine U.S. inches to Metric millimeters, and vice versa. You may choose Tap/Drill conversions to display recommended drill sizes for common taps or use the Drill Size conversions to display decimal equivalents for common drill sizes.
Conversion Calculator:

Enter an Inch or Metric Value below, then press "Convert"

Inch (in. or ")

Millimeter (mm)
Tap to Drill Size Charts:
Drill Size to Decimal Charts:
Tap
Size
-Pitch= Tap Drill
Tap
Size
- Pitch = Tap Drill
Tap
Size
- Pitch = Tap Drill
0 - 80 = 3/64
1 - 64 = 53
1 - 72 = 53
2 - 56 = 50
2 - 64 = 50
3 - 48 = 47
3 - 56 = 45
4 - 40 = 43
4 - 48 = 42
5 - 40 = 38
5 - 44 = 37
6 - 32 = 36
6 - 40 = 33
8 - 32 = 29
8 - 36 = 29
10 - 24 = 25
10 - 32 = 21
12 - 24 = 16
12 - 28 = 14
1/4 - 20 = 7
1/4 - 28 = 3
5/16 - 18 = F
5/16 - 24 = I
3/8 - 16 = 5/16
3/8 - 24 = Q
7/16 - 14 = U
7/16 - 20 = 25/64
1/2 - 13 = 27/64
1/2 - 20 = 29/64
9/16 - 12 = 31/64
9/16 - 18 = 1/2
5/8 - 11 = 17/32
5/8 - 18 = 9/16
11/16 - 11 = 19/32
11/16 - 16 = 5/8
3/4 - 10 = 21/32
3/4 - 16 = 11/16
7/8 - 9 = 49/64
7/8 - 14 = 49/64
1 - 8 = 7/8
1 - 12 = 59/64
1 - 14 = 59/64
1 1/8 - 7 = 63/64
1 1/8 - 12 = 1 1/32
1 1/4 - 7 = 1 7/64
1 1/4 - 12 = 1 11/64
1 1/2 - 6 = 1 11/32
1 1/2 - 12 = 1 27/64
1 3/4 - 5 = 1 9/16
2 - 4 1/2 = 1 25/32
1/8 - 27 = 11/32
1/4 - 18 = 7/16
3/8 - 18 = 37/64
1/2 - 14 = 23/32
3/4 - 14 = 59/64
1 - 11 1/2 = 1 5/32
1 1/4 - 11 1/2 = 1 1/2
1 1/2 - 11 1/2 = 1 3/4
2 - 11 1/2 = 2 7/32
1 1/16 - 27 = C
1 1/8 - 27 = Q
1/4 - 18 = 7/16
3/8 - 18 = 9/16
1/2 - 14 = 45/64
3/4 - 14 = 29/32
1 - 11 1/2 = 1 9/64
1 1/4 - 11 1/2 = 1 31/64
1 1/2 - 11 1/2 = 1 23/32
2 - 11 1/2 = 2 3/16

Tap Size

-

 Pitch MM =
Drill MM
Tap Size

-

 Pitch MM =
Drill MM
M 1.6 x 0.35 = 1.25
M 2 x 0.40 = 1.60
M 2.5 x 0.45 = 2.05
M 3 x 0.50 = 2.50
M 4 x 0.70 = 3.30
M 5 x 0.80 = 4.20
M 6 x 1.00 = 5.00
M 7 x 1.00 = 6.00
M 8 x 1.25 = 6.80
M 10 x 1.50 = 8.50
M 12 x 1.75 = 10.2
M 14 x 2.00 = 12.0
M 16 x 2.00 = 14.0
M 18 x 2.50 = 15.5
M 20 x 2.50 = 17.5
M 24 x 3.00 = 21.0
M 30 x 3.50 = 26.5
M 36 x 4.00 = 32.0

Fraction = Decimal
Fraction = Decimal
Fraction = Decimal
1 / 64 = .0156
1 / 32 = .0312
3 / 64 = .0469
1 / 16 = .0625
5 / 64 = .0781
3 / 32 = .0938
7 / 64 = .1094
1 / 8 = .1250
9 / 64 = .1406
5 / 32 = .1562
11 / 64 = .1719
3 / 16 = .1875
13 / 64 = .2031
7 / 32 = .2188
15 / 64 = .2344
1 / 4 = .2500
17 / 64 = .2656
9 / 32 = .2812
19 / 64 = .2969
5 / 16 = .3125
21 / 64 = .3281
11 / 32 = .3438
23 / 64 = .3594
3 / 8 = .3750
25 / 64 = .3906
13 / 32 = .4062
27 / 64 = .4219
7 / 16 = .4375
29 / 64 = .4531
15 / 32 = .4688
31 / 64 = .4844
1 / 2 = .5000
33 / 64 = .5156
17 / 32 = .5312
35 / 64 = .5469
9 / 16 = .5625
37 / 64 = .5781
19 / 32 = .5938
39 / 64 = .6094
5 / 8 = .6250
41 / 64 = .6406
21 / 32 = .6562
43 / 64 = .6719
11 / 16 = .6875
45 / 64 = .7031
23 / 32 = .7188
47 / 64 = .7344
3 / 4 = .7500
49 / 64 = .7656
25 / 32 = .7812
51 / 64 = .7969
13 / 16 = .8125
53 / 64 = .8281
27 / 32 = .8438
55 / 64 = .8594
7 / 8 = .8750
57 / 64 = .8906
29 / 32 = .9062
59 / 64 = .9219
15 / 16 = .9375
61 / 64 = .9531
31 / 32 = .9688
63 / 64 = .9844

Wire
Size
= Decimal
Wire
Size
= Decimal
Wire
Size
= Decimal
Wire
Size
= Decimal
80 = .0135
79 = .0145
78 = .0160
77 = .0180
76 = .0200
75 = .0210
74 = .0225
73 = .0240
72 = .0250
71 = .0260
70 = .0280
69 = .0292
68 = .0310
67 = .0320
66 = .0330
65 = .0350
64 = .0360
63 = .0370
62 = .0380
61 = .0390
60 = .0400
59 = .0410
58 = .0420
57 = .0430
56 = .0465
55 = .0520
54 = .0550
53 = .0595
52 = .0635
51 = .0670
50 = .0700
49 = .0730
48 = .0760
47 = .0785
46 = .0810
45 = .0820
44 = .0860
43 = .0890
42 = .0935
41 = .0960
40 = .0980
39 = .0995
38 = .1015
37 = .1040
36 = .1065
35 = .1100
34 = .1110
33 = .1130
32 = .1160
31 = .1200
30 = .1285
29 = .1360
28 = .1405
27 = .1440
26 = .1470
25 = .1495
24 = .1520
23 = .1540
22 = .1570
21 = .1590
20 = .1610
19 = .1660
18 = .1695
17 = .1730
16 = .1770
15 = .1800
14 = .1820
13 = .1850
12 = .1890
11 = .1910
10 = .1935
9 = .1960
8 = .1990
7 = .2010
6 = .2040
5 = .2055
4 = .2090
3 = .2130
2 = .2210
1 = .2280
A = .2340
B = .2380
C = .2420
D = .2460
E = .2500
F = .2570
G = .2610
H = .2660
I = .2720
J = .2770
K = .2810
L = .2900
M = .2950
N = .3020
O = .3160
P = .3230
Q = .3320
R = .3390
S = .3480
T = .3580
U = .3680
V = .3770
W= .3860
X = .3970
Y = .4040
Z = .4130