Data Charts And Reference Tables

Standard Drill Sizes and Decimal Equivalents

Standard Drill Sizes Superseding Gauge and Letter Sizes

Inches	Milimeters	Decimal
	0.20	0.0079
	0.22	0.0087
	0.25	0.0099
	0.28	0.0110
	0.30	0.0118
	0.32	0.0126
	0.35	0.0138
	0.38	0.0150
1/64		0.0156
	0.40	0.0157
	0.42	0.0165
	0.45	0.0177
	0.48	0.0189
	0.50	0.0197
	0.52	0.0205
	0.55	0.0217
	0.58	0.0228
	0.60	0.0236
	0.62	0.0244
	0.65	0.0256
	0.68	0.0268
	0.70	0.0276
	0.72	0.0283
	0.75	0.0295
	0.78	0.0307
1/32		0.0312
	0.80	0.0315
	0.82	0.0323
	0.85	0.0335
	0.88	0.0346
	0.90	0.0354
	0.92	0.0362
	0.95	0.0374
	0.98	0.0386
	1.00	0.0394
	1.05	0.0413
	1.10	0.0433
	1.15	0.0453
3/64		0.0469
	1.20	0.0472
	1.25	0.0492
	1.30	0.0512
	1.35	0.0532
	1.40	0.0551
	1.45	0.0571
	1.50	0.0591
	1.55	0.0610
1/16		0.0625
	1.60	0.0630
	1.65	0.0650

Inches	Millimeters	Decimal
	1.70	0.0669
	1.75	0.0689
	1.80	0.0709
	1.85	0.0728
	1.90	0.0748
	1.95	0.0768
5/64		0.0781
	2.00	0.0787
	2.05	0.0807
	2.10	0.0827
	2.15	0.0846
	2.20	0.0866
	2.25	0.0886
	2.30	0.0906
	2.35	0.0925
3/36		0.0938
	2.40	0.0945
	2.45	0.0965
	2.50	0.0984
	2.55	0.1004
	2.60	0.1024
	2.65	0.1034
	2.70	0.1063
	2.75	0.1083
7/64		0.1094
	2.80	0.1102
	2.85	0.1122
	2.90	0.1142
	2.95	0.1161
	3.00	0.1181
	3.10	0.1220
1/8		0.1250
	3.20	0.1260
	3.30	0.1299
	3.40	0.1339
	3.50	0.1378
9/64		0.1406
	3.60	0.1417
	3.70	0.1457
	3.80	0.1496
	3.90	0.1535
6/32		0.1562
	4.00	0.1575
	4.10	0.1614
	4.20	0.1654
	4.30	0.1693
11/64		0.1719
	4.40	0.1732
	4.50	0.1772
	4.60	0.1811

Inches	Millimeters	Decimal
	4.70	0.1850
3/16		0.1875
	4.80	0.1890
	4.90	0.1929
	5.00	0.1968
	5.10	0.2008
13/64		0.2031
	5.20	0.2047
	5.30	0.2087
	5.40	0.2126
	5.50	0.2165
7/32		0.2188
	5.60	0.2205
	5.70	0.2244
	5.80	0.2283
	5.90	0.2323
16/64		0.2344
	6.00	0.2362
	6.10	0.2402
	6.20	0.2441
	6.30	0.2480
1/4		0.2500
	6.40	0.2520
	6.50	0.2559
	6.60	0.2598
	6.70	0.2638
17/64		0.2656
	6.80	0.2677
	6.90	0.2717
	7.00	0.2756
	7.10	0.2795
8/32		0.2812
	7.20	0.2835
	7.30	0.2874
	7.40	0.2913
	7.50	0.2953
19/64		0.2969
	7.60	0.2992
	7.70	0.3032
	7.80	0.3071
	7.90	0.3110
6/16		0.3125
	8.00	0.3150
	8.10	0.3189
	8.20	0.3228
	8.30	0.3268
21/64		0.3281
	8.40	0.3307
	8.50	0.3346
	8.60	0.3386

Number	Standard Metric Size
80	0.35
79	0.38
78	0.40
77	0.45
76	0.50
75	0.52
74	0.58
73	0.60
72	0.62
71	0.65
70	0.70
69	0.75
68	1/32
67	0.82
66	0.84
65	0.90
64	0.92
63	0.95
62	0.98
61	1.00
60	1.02
59	1.05
58	1.07
57	1.10
56	3/64
55	1.30
54	1.40
53	1.52
52	1.62
51	1.70
50	1.80
49	1.85
48	1.92
47	2.00
46	2.05
45	2.10
44	2.20
43	2.25
42	3/32
41	2.45
40	2.50
39	2.55
38	2.60
37	2.65
36	2.70
35	2.80
34	2.82
33	2.85
32	2.95
31	3.05

Standard Drill Sizes and Decimal Equivalents

Standard Drill Sizes Superseding Gauge and Letter Sizes

Inches	Millimeters	Decimal
	8.70	0.3425
11/32		0.3438
	8.80	0.3465
	8.90	0.3504
	9.00	0.3543
	9.10	0.3583
23/64		0.3594
	9.20	0.3622
	9.30	0.3661
	9.40	0.3701
	9.50	0.3740
3/8		0.3750
	9.60	0.3780
	9.70	0.3819
	9.80	0.3858
	9.90	0.3898
25/64		0.3896
	10.00	0.3937
	10.10	0.3976
	10.20	0.4016
	10.30	0.4055
13/32		0.4062
	10.40	0.4094
	10.50	0.4134
	10.60	0.4173
	10.70	0.4213
27/64		0.4219
	10.80	0.4252
	10.90	0.4291
	11.00	0.4331
	11.10	0.4370
7/16		0.4375
	11.20	0.4409
	11.30	0.4449
	11.40	0.4488
	11.50	0.4528
29/64		0.4531
	11.60	0.4567
	11.70	0.4606
	11.80	0.4646
	11.90	0.4685
15/32		0.4688
	12.00	0.4724
	12.10	0.4764
	12.20	0.4803
	12.30	0.4843
31/64		0.4844
	12.40	0.4882
	12.50	0.4921

Inches	Millimeters	Decimal
	12.60	0.4961
	12.70	0.5000
	12.80	0.5039
	12.90	0.5079
	13.00	0.5118
33/64		0.5156
	13.10	0.5157
	13.20	0.5197
	13.30	0.5326
	13.40	0.5276
17/32		0.5312
	13.50	0.5315
	13.60	0.5354
	13.70	0.5394
	13.80	0.5433
35/64		0.5469
	13.90	0.5472
	14.00	0.5512
	14.25	0.5610
9/16		0.5625
	14.50	0.5709
37/64		0.5781
	14.75	0.5827
	15.00	0.5906
19/32		0.5938
	15.25	0.6004
39/64		0.6094
	15.50	0.6102
	15.75	0.6201
5/8		0.6250
	16.00	0.6299
	16.25	0.6398
41/64		0.6406
	16.50	0.6496
21/32		0.6562
	16.75	0.6594
	17.00	0.6693
43/64		0.6719
	17.25	0.6791
11/16		0.6875
	17.50	0.6890
	17.75	0.6988
45/64		0.7031
	18.00	0.7087
	18.25	0.7185
26/32		0.7188
	18.50	0.7283
47/64		0.7344
	18.75	0.7382

Inches	Millimeters	Decimal
	19.00	0.7480
3/4		0.7500
	19.25	0.7579
49/64		0.7656
	19.50	0.7677
	19.75	0.7776
25/32		0.7812
	20.00	0.7874
51/64		0.7969
	20.25	0.7972
	20.50	0.8071
13/16		0.8125
	20.75	0.8169
	21.00	0.8268
53/64		0.8281
	21.25	0.8366
27/32		0.8438
	21.50	0.8465
	21.75	0.8563
55/64		0.8594
	22.00	0.8661
7/8		0.8750
	22.25	0.8760
	22.50	0.8858
57/64		0.8906
	22.75	0.8957
	23.00	0.9055
29/32		0.9062
	23.25	0.9154
39/64		0.9219
	23.50	0.9252
	23.75	0.9350
15/16		0.9375
	24.00	0.9449
61/64		0.9531
	24.25	0.9547
	24.50	0.9646
31/32		0.9688
	24.75	0.9744
	25.00	0.9843
63/64		0.9844
1		1.0000

Standards Rise in Increments of 1/64inches and 0.50 mm

Number or Letter	Standard Metric Size
30	3.25
29	3.45
28	9/64
27	3.65
26	3.70
25	3.80
24	3.90
23	3.92
22	4.00
21	4.02
20	4.10
19	4.20
18	4.30
17	4.40
16	4.50
15	4.58
14	4.62
13	4.70
12	4.80
11	4.85
10	4.90
9	5.00
8	5.08
7	5.10
6	5.20
5	5.22
4	5.30
3	5.40
2	5.60
1	5.80
A	5.80
B	6.05
C	6.15
D	6.25
E	6.35
F	6.55
G	6.65
H	6.76
I	6.95
J	7.05
K	7.15
L	7.35
M	7.45
N	7.65
O	8.05
P	8.20
Q	8.45
R	8.65
S	8.85
T	9.10
U	9.35
V	9.55
W	9.80
X	10.10
Y	10.30
Z	10.50

I.S.O. Metric Fine Threads in Millimeters

d=D : Major Diameter
p : Pitch
r : Root Radius
d2=D2 : Pitch Diameter
d3 : Minor Diameter Male Thread
D1 : Minor Diameter Female Thread
h3 : Thread Height Male
H1 : Thread Height Female

Size	d=D (mm)	p (mm)	r (mm)	d2=D2 (mm)	d3 (mm)	D1 (mm)	h3 (mm)	H1 (mm)	Tapp Drill (mm)
M1.0 x 0.20	1.0	0.20	0.029	0.870	0.755	0.783	0.108	0.108	0.80
M1.1 x 0.20	1.1	0.20	0.029	0.970	0.855	0.883	0.123	0.108	0.90
M1.2 x 0.20	1.2	0.20	0.029	1.070	0.955	0.983	0.123	0.108	1.00
M1.4 x 0.20	1.4	0.20	0.029	1.270	1.155	1.183	0.123	0.108	1.20
M1.6 x 0.20	1.6	0.20	0.029	1.470	1.355	1.383	0.123	0.108	1.40
M1.8 x 0.20	1.8	0.20	0.029	1.670	1.555	1.583	0.123	0.108	1.60
M2 x 0.25	2.0	0.25	0.036	1.838	1.693	1.729	0.153	0.135	1.75
M2.2 x 0.25	2.2	0.25	0.036	2.038	1.893	1.929	0.153	0.135	1.95
M2.5 x 0.35	2.5	0.35	0.051	2.273	2.071	2.121	0.215	0.189	2.10
M3 x 0.35	3.0	0.35	0.051	2.773	2.571	2.621	0.215	0.189	2.60
M3.5 x 0.35	3.5	0.35	0.051	3.273	3.071	3.121	0.215	0.189	3.10
M4 x 0.50	4.0	0.50	0.072	3.675	3.387	3.459	0.307	0.271	3.50
M4.5 x 0.50	4.5	0.50	0.072	4.175	3.887	3.959	0.307	0.271	4.00
M5 x 0.50	5.0	0.50	0.072	4.675	4.387	4.459	0.307	0.271	4.50
M5.5 x 0.50	5.5	0.50	0.072	5.175	4.887	4.959	0.307	0.271	5.00
M6 x 0.75	6.0	0.75	0.108	5.513	5.080	5.188	0.460	0.406	5.20
M7 x 0.75	7.0	0.75	0.108	6.513	6.080	6.188	0.460	0.406	6.20
M8 x 0.75	8.0	0.75	0.108	7.513	7.080	7.188	0.460	0.406	7.20
M8 x 1.00	8.0	1.00	0.144	7.350	6.773	6.917	0.613	0.541	7.00
M9 x 0.75	9.0	0.75	0.108	8.513	8.080	8.188	0.460	0.406	8.20
M9 x 1.00	9.0	1.00	0.144	8.350	7.773	7.917	0.613	0.541	8.00
M10 x 0.75	10.0	0.75	0.108	9.513	9.080	9.188	0.460	0.406	9.20
M10 x 1.00	10.0	1.00	0.144	9.350	8.773	8.917	0.613	0.541	9.00
M10 x 1.25	10.0	1.25	0.180	9.188	8.466	8.647	0.767	0.677	8.80
M11 x 0.75	11.0	0.75	0.108	10.513	10.080	10.188	0.460	0.406	10.20
M11 x 1.00	11.0	1.00	0.144	10.350	9.773	9.917	0.613	0.541	10.00
M12 x 1.00	12.0	1.00	0.144	11.350	10.773	10.917	0.613	0.541	11.00
M12 x 1.25	12.0	1.25	0.180	11.188	10.466	10.647	0.767	0.677	10.80
M12 x 1.50	12.0	1.50	0.217	11.026	10.160	10.376	0.920	0.812	10.50
M14 x 1.00	14.0	1.00	0.144	13.35	12.773	12.917	0.613	0.541	13.00
M14 x 1.25	14.0	1.25	0.180	13.188	12.466	12.647	0.767	0.677	12.80
M14 x 1.50	14.0	1.50	0.217	13.026	12.160	12.376	0.920	0.812	12.50
M15 x 1.00	15.0	1.00	0.144	14.350	13.773	13.917	0.613	0.541	14.00
M15 x 1.50	15.0	1.50	0.217	14.026	13.160	13.376	0.920	0.812	13.50
M16 x 1.00	16.0	1.00	0.144	15.350	14.773	14.917	0.613	0.541	15.00
M16 x 1.50	16.0	1.50	0.217	15.026	14.160	14.376	0.920	0.812	14.50
M17 x 1.00	17.0	1.00	0.144	16.350	15.773	15.917	0.613	0.541	16.00
M17 x 1.50	17.0	1.50	0.217	16.026	15.160	15.376	0.920	0.812	15.50
M18 x 1.00	18.0	1.00	0.144	17.350	16.773	16.917	0.613	0.541	17.00
M18 x 1.50	18.0	1.50	0.217	17.026	16.160	16.376	0.920	0.812	16.50
M18 x 2.00	18.0	2.00	0.289	16.701	15.546	15.835	1.227	1.083	16.00
M20 x 1.00	20.0	1.00	0.144	19.350	18.773	18.917	0.613	0.541	19.00
M20 x 1.50	20.0	1.50	0.217	19.026	18.160	18.376	0.920	0.812	18.50
M20 x 2.00	20.0	2.00	0.289	18.701	17.546	17.835	1.227	1.083	18.00
M22 x 1.00	22..0	1.00	0.144	21.350	20.773	20.917	0.613	0.541	21.00
M22 x 1.50	22.0	1.50	0.217	21.026	20.160	20.376	0.920	0.812	20.50
M22 x 2.00	22.0	2.00	0.289	20.701	19.546	19.835	1.227	1.083	20.00
M24 x 1.00	24.0	1.00	0.144	23.350	22.773	22.917	0.613	0.541	23.00
M24 x 1.50	24.0	1.50	0.217	23.026	22.160	22.376	0.920	0.812	22.50
M24 x 2.00	24.0	2.00	0.289	22.701	21.546	21.835	1.227	1.083	22.00
M25 x 1.00	25.0	1.00	0.144	24.350	23.773	23.917	0.613	0.541	24.00
M25 x 1.50	25.0	1.50	0.217	24.026	23.160	23.376	0.920	0.812	23.50
M25 x 2.00	25.0	2.00	0.289	23.701	22.546	22.835	1.227	1.083	23.00
M27 x 1.00	27.0	1.00	0.144	26.350	25.773	25.917	0.613	0.541	26.00
M27 x 1.50	27.0	1.50	0.217	26.026	25.160	25.376	0.920	0.812	25.50
M27 x 2.00	27.0	2.00	0.289	25.701	24.546	24.835	1.227	1.083	25.00
M28 x 1.00	28.0	1.00	0.144	27.350	26.773	26.917	0.613	0.541	27.00
M28 x 1.50	28.0	1.50	0.217	27.026	26.160	26.376	0.920	0.812	26.50
M28 x 2.00	28.0	2.00	0.289	26.701	25.546	25.835	1.227	1.083	26.00
M30 x 1.00	30.0	1.00	0.144	29.350	28.773	28.917	0.613	0.541	29.00
M30 x 1.50	30.0	1.50	0.217	29.026	28.160	28.376	0.920	0.812	28.50
M30 x 2.00	30.0	2.00	0.289	28.701	27.546	27.835	1.227	1.083	28.00
M30 x 3.00	30.0	3.00	0.433	28.051	26.319	26.752	1.840	1.624	27.00

BA Standard Tapping Drills

Last Updated : 16th July 2025