Drill bit size chart

164 named designations: fractional 1/64–1/2 in by 1/64, number #80–#1, letters A–Z, metric 0.5–13.0 mm by 0.5 mm. Converted at exactly 1 in = 25.4 mm. Source precision is preserved; converted values are rounded half-up to four places in mm or six in inches.

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164 OF 164 ROWS

DESIGNATION	FAMILY	Ø MM	Ø IN
#80	number	0.3429	0.0135
#79	number	0.3683	0.0145
1/64	fractional	0.3969	0.015625
#78	number	0.4064	0.0160
#77	number	0.4572	0.0180
0.5 mm	metric	0.5	0.019685
#76	number	0.508	0.0200
#75	number	0.5334	0.0210
#74	number	0.5715	0.0225
#73	number	0.6096	0.0240
#72	number	0.635	0.0250
#71	number	0.6604	0.0260
#70	number	0.7112	0.0280
#69	number	0.7417	0.0292
#68	number	0.7874	0.0310
1/32	fractional	0.7938	0.03125
#67	number	0.8128	0.0320
#66	number	0.8382	0.0330
#65	number	0.889	0.0350
#64	number	0.9144	0.0360
#63	number	0.9398	0.0370
#62	number	0.9652	0.0380
#61	number	0.9906	0.0390
1.0 mm	metric	1.0	0.03937
#60	number	1.016	0.0400
#59	number	1.0414	0.0410
#58	number	1.0668	0.0420
#57	number	1.0922	0.0430
#56	number	1.1811	0.0465
3/64	fractional	1.1906	0.046875
#55	number	1.3208	0.0520
#54	number	1.397	0.0550
1.5 mm	metric	1.5	0.059055
#53	number	1.5113	0.0595
1/16	fractional	1.5875	0.0625
#52	number	1.6129	0.0635
#51	number	1.7018	0.0670
#50	number	1.778	0.0700
#49	number	1.8542	0.0730
#48	number	1.9304	0.0760
5/64	fractional	1.9844	0.078125
#47	number	1.9939	0.0785
2.0 mm	metric	2.0	0.07874
#46	number	2.0574	0.0810
#45	number	2.0828	0.0820
#44	number	2.1844	0.0860
#43	number	2.2606	0.0890
#42	number	2.3749	0.0935
3/32	fractional	2.3813	0.09375
#41	number	2.4384	0.0960
#40	number	2.4892	0.0980
2.5 mm	metric	2.5	0.098425
#39	number	2.5273	0.0995
#38	number	2.5781	0.1015
#37	number	2.6416	0.1040
#36	number	2.7051	0.1065
7/64	fractional	2.7781	0.109375
#35	number	2.794	0.1100
#34	number	2.8194	0.1110
#33	number	2.8702	0.1130
#32	number	2.9464	0.1160
3.0 mm	metric	3.0	0.11811
#31	number	3.048	0.1200
1/8	fractional	3.175	0.125
#30	number	3.2639	0.1285
#29	number	3.4544	0.1360
3.5 mm	metric	3.5	0.137795
#28	number	3.5687	0.1405
9/64	fractional	3.5719	0.140625
#27	number	3.6576	0.1440
#26	number	3.7338	0.1470
#25	number	3.7973	0.1495
#24	number	3.8608	0.1520
#23	number	3.9116	0.1540
5/32	fractional	3.9688	0.15625
#22	number	3.9878	0.1570
4.0 mm	metric	4.0	0.15748
#21	number	4.0386	0.1590
#20	number	4.0894	0.1610
#19	number	4.2164	0.1660
#18	number	4.3053	0.1695
11/64	fractional	4.3656	0.171875
#17	number	4.3942	0.1730
#16	number	4.4958	0.1770
4.5 mm	metric	4.5	0.177165
#15	number	4.572	0.1800
#14	number	4.6228	0.1820
#13	number	4.699	0.1850
3/16	fractional	4.7625	0.1875
#12	number	4.8006	0.1890
#11	number	4.8514	0.1910
#10	number	4.9149	0.1935
#9	number	4.9784	0.1960
5.0 mm	metric	5.0	0.19685
#8	number	5.0546	0.1990
#7	number	5.1054	0.2010
13/64	fractional	5.1594	0.203125
#6	number	5.1816	0.2040
#5	number	5.2197	0.2055
#4	number	5.3086	0.2090
#3	number	5.4102	0.2130
5.5 mm	metric	5.5	0.216535
7/32	fractional	5.5563	0.21875
#2	number	5.6134	0.2210
#1	number	5.7912	0.2280
A	letter	5.9436	0.2340
15/64	fractional	5.9531	0.234375
6.0 mm	metric	6.0	0.23622
B	letter	6.0452	0.2380
C	letter	6.1468	0.2420
D	letter	6.2484	0.2460
1/4	fractional	6.35	0.25
E	letter	6.35	0.2500
6.5 mm	metric	6.5	0.255906
F	letter	6.5278	0.2570
G	letter	6.6294	0.2610
17/64	fractional	6.7469	0.265625
H	letter	6.7564	0.2660
I	letter	6.9088	0.2720
7.0 mm	metric	7.0	0.275591
J	letter	7.0358	0.2770
K	letter	7.1374	0.2810
9/32	fractional	7.1438	0.28125
L	letter	7.366	0.2900
M	letter	7.493	0.2950
7.5 mm	metric	7.5	0.295276
19/64	fractional	7.5406	0.296875
N	letter	7.6708	0.3020
5/16	fractional	7.9375	0.3125
8.0 mm	metric	8.0	0.314961
O	letter	8.0264	0.3160
P	letter	8.2042	0.3230
21/64	fractional	8.3344	0.328125
Q	letter	8.4328	0.3320
8.5 mm	metric	8.5	0.334646
R	letter	8.6106	0.3390
11/32	fractional	8.7313	0.34375
S	letter	8.8392	0.3480
9.0 mm	metric	9.0	0.354331
T	letter	9.0932	0.3580
23/64	fractional	9.1281	0.359375
U	letter	9.3472	0.3680
9.5 mm	metric	9.5	0.374016
3/8	fractional	9.525	0.375
V	letter	9.5758	0.3770
W	letter	9.8044	0.3860
25/64	fractional	9.9219	0.390625
10.0 mm	metric	10.0	0.393701
X	letter	10.0838	0.3970
Y	letter	10.2616	0.4040
13/32	fractional	10.3188	0.40625
Z	letter	10.4902	0.4130
10.5 mm	metric	10.5	0.413386
27/64	fractional	10.7156	0.421875
11.0 mm	metric	11.0	0.433071
7/16	fractional	11.1125	0.4375
11.5 mm	metric	11.5	0.452756
29/64	fractional	11.5094	0.453125
15/32	fractional	11.9063	0.46875
12.0 mm	metric	12.0	0.472441
31/64	fractional	12.3031	0.484375
12.5 mm	metric	12.5	0.492126
1/2	fractional	12.7	0.5
13.0 mm	metric	13.0	0.511811
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PRINTABLE COMMON-SIZE CHART

A full reference sheet with source attribution, exact conversion and dataset version.

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Common drill size chart with all 164 designations, millimetres, decimal inches and source references

SOURCE Metric, Inch & Fractional Inch shop size table · v.2, 2007-02-12; Manufacturing Processes 4-5 — Unit 5: Tapping · Archived 2026-04-15; accessed 2026-09-09; bd_warehouse tap hole sizes · 4006fb03b2a022d11abd41fc4c24a3a042f25ea0 · 1 IN = 25.4 MM EXACTLY
CircuitousRoot shop size table v.2 (2007-02-12). Public Domain. Fractions and conversions recalculated.; Adapted from Unit 5: Tapping, LamNgeun Virasak, Open Oregon. CC BY 4.0: https://creativecommons.org/licenses/by/4.0/ . Selected rows; wording adapted.; bd_warehouse, Copyright 2024 Gumyr. Apache License 2.0. Selected Soft-column values; presentation adapted. Licence: fasteneratlas.com/licenses/bd-warehouse-Apache-2.0.txt.
DATASET 2026.09.09