Universal Drill Size Chart

Every standard twist drill size — fractional inch, number (wire gauge), letter, and metric — merged into one table and sorted by diameter. Click any size for equivalents, neighbors, and tap-drill uses. Values per ASME B94.11M; conversions are exact (25.4 mm/in). Printable wall chart: drill-chart.pdf.

Where each system lives: number and letter drills are one continuous gauge sequence; fractional and metric interleave across the whole range.

Drill	System	Decimal in	mm
#80	Number	0.0135	0.343
#79	Number	0.0145	0.368
1/64″	Fractional	0.0156	0.397
#78	Number	0.0160	0.406
#77	Number	0.0180	0.457
#76	Number	0.0200	0.508
#75	Number	0.0210	0.533
#74	Number	0.0225	0.571
#73	Number	0.0240	0.61
#72	Number	0.0250	0.635
#71	Number	0.0260	0.66
#70	Number	0.0280	0.711
#69	Number	0.0292	0.742
#68	Number	0.0310	0.787
1/32″	Fractional	0.0313	0.794
#67	Number	0.0320	0.813
#66	Number	0.0330	0.838
#65	Number	0.0350	0.889
#64	Number	0.0360	0.914
#63	Number	0.0370	0.94
#62	Number	0.0380	0.965
#61	Number	0.0390	0.991
1 mm	Metric	0.0394	1
#60	Number	0.0400	1.016
#59	Number	0.0410	1.041
#58	Number	0.0420	1.067
#57	Number	0.0430	1.092
1.1 mm	Metric	0.0433	1.1
#56	Number	0.0465	1.181
3/64″	Fractional	0.0469	1.191
1.2 mm	Metric	0.0472	1.2
1.25 mm	Metric	0.0492	1.25
1.3 mm	Metric	0.0512	1.3
#55	Number	0.0520	1.321
#54	Number	0.0550	1.397
1.4 mm	Metric	0.0551	1.4
1.5 mm	Metric	0.0591	1.5
#53	Number	0.0595	1.511
1/16″	Fractional	0.0625	1.587
1.6 mm	Metric	0.0630	1.6
#52	Number	0.0635	1.613
1.7 mm	Metric	0.0669	1.7
#51	Number	0.0670	1.702
#50	Number	0.0700	1.778
1.8 mm	Metric	0.0709	1.8
#49	Number	0.0730	1.854
1.9 mm	Metric	0.0748	1.9
#48	Number	0.0760	1.93
5/64″	Fractional	0.0781	1.984
#47	Number	0.0785	1.994
2 mm	Metric	0.0787	2
2.05 mm	Metric	0.0807	2.05
#46	Number	0.0810	2.057
#45	Number	0.0820	2.083
2.1 mm	Metric	0.0827	2.1
#44	Number	0.0860	2.184
2.2 mm	Metric	0.0866	2.2
#43	Number	0.0890	2.261
2.3 mm	Metric	0.0906	2.3
#42	Number	0.0935	2.375
3/32″	Fractional	0.0938	2.381
2.4 mm	Metric	0.0945	2.4
#41	Number	0.0960	2.438
#40	Number	0.0980	2.489
2.5 mm	Metric	0.0984	2.5
#39	Number	0.0995	2.527
#38	Number	0.1015	2.578
2.6 mm	Metric	0.1024	2.6
#37	Number	0.1040	2.642
2.7 mm	Metric	0.1063	2.7
#36	Number	0.1065	2.705
7/64″	Fractional	0.1094	2.778
#35	Number	0.1100	2.794
2.8 mm	Metric	0.1102	2.8
#34	Number	0.1110	2.819
#33	Number	0.1130	2.87
2.9 mm	Metric	0.1142	2.9
#32	Number	0.1160	2.946
3 mm	Metric	0.1181	3
#31	Number	0.1200	3.048
3.1 mm	Metric	0.1220	3.1
1/8″	Fractional	0.1250	3.175
3.2 mm	Metric	0.1260	3.2
#30	Number	0.1285	3.264
3.3 mm	Metric	0.1299	3.3
3.4 mm	Metric	0.1339	3.4
#29	Number	0.1360	3.454
3.5 mm	Metric	0.1378	3.5
#28	Number	0.1405	3.569
9/64″	Fractional	0.1406	3.572
3.6 mm	Metric	0.1417	3.6
#27	Number	0.1440	3.658
3.7 mm	Metric	0.1457	3.7
#26	Number	0.1470	3.734
#25	Number	0.1495	3.797
3.8 mm	Metric	0.1496	3.8
#24	Number	0.1520	3.861
3.9 mm	Metric	0.1535	3.9
#23	Number	0.1540	3.912
5/32″	Fractional	0.1563	3.969
#22	Number	0.1570	3.988
4 mm	Metric	0.1575	4
#21	Number	0.1590	4.039
#20	Number	0.1610	4.089
4.1 mm	Metric	0.1614	4.1
4.2 mm	Metric	0.1654	4.2
#19	Number	0.1660	4.216
4.3 mm	Metric	0.1693	4.3
#18	Number	0.1695	4.305
11/64″	Fractional	0.1719	4.366
#17	Number	0.1730	4.394
4.4 mm	Metric	0.1732	4.4
#16	Number	0.1770	4.496
4.5 mm	Metric	0.1772	4.5
#15	Number	0.1800	4.572
4.6 mm	Metric	0.1811	4.6
#14	Number	0.1820	4.623
#13	Number	0.1850	4.699
4.7 mm	Metric	0.1850	4.7
3/16″	Fractional	0.1875	4.762
4.8 mm	Metric	0.1890	4.8
#12	Number	0.1890	4.801
#11	Number	0.1910	4.851
4.9 mm	Metric	0.1929	4.9
#10	Number	0.1935	4.915
#9	Number	0.1960	4.978
5 mm	Metric	0.1969	5
#8	Number	0.1990	5.055
5.1 mm	Metric	0.2008	5.1
#7	Number	0.2010	5.105
13/64″	Fractional	0.2031	5.159
#6	Number	0.2040	5.182
5.2 mm	Metric	0.2047	5.2
#5	Number	0.2055	5.22
5.3 mm	Metric	0.2087	5.3
#4	Number	0.2090	5.309
5.4 mm	Metric	0.2126	5.4
#3	Number	0.2130	5.41
5.5 mm	Metric	0.2165	5.5
7/32″	Fractional	0.2188	5.556
5.6 mm	Metric	0.2205	5.6
#2	Number	0.2210	5.613
5.7 mm	Metric	0.2244	5.7
#1	Number	0.2280	5.791
5.8 mm	Metric	0.2283	5.8
5.9 mm	Metric	0.2323	5.9
A	Letter	0.2340	5.944
15/64″	Fractional	0.2344	5.953
6 mm	Metric	0.2362	6
B	Letter	0.2380	6.045
6.1 mm	Metric	0.2402	6.1
C	Letter	0.2420	6.147
6.2 mm	Metric	0.2441	6.2
D	Letter	0.2460	6.248
6.3 mm	Metric	0.2480	6.3
E	Letter	0.2500	6.35
1/4″	Fractional	0.2500	6.35
6.4 mm	Metric	0.2520	6.4
6.5 mm	Metric	0.2559	6.5
F	Letter	0.2570	6.528
6.6 mm	Metric	0.2598	6.6
G	Letter	0.2610	6.629
6.7 mm	Metric	0.2638	6.7
17/64″	Fractional	0.2656	6.747
H	Letter	0.2660	6.756
6.8 mm	Metric	0.2677	6.8
6.9 mm	Metric	0.2717	6.9
I	Letter	0.2720	6.909
7 mm	Metric	0.2756	7
J	Letter	0.2770	7.036
7.1 mm	Metric	0.2795	7.1
K	Letter	0.2810	7.137
9/32″	Fractional	0.2813	7.144
7.2 mm	Metric	0.2835	7.2
7.3 mm	Metric	0.2874	7.3
L	Letter	0.2900	7.366
7.4 mm	Metric	0.2913	7.4
M	Letter	0.2950	7.493
7.5 mm	Metric	0.2953	7.5
19/64″	Fractional	0.2969	7.541
7.6 mm	Metric	0.2992	7.6
N	Letter	0.3020	7.671
7.7 mm	Metric	0.3031	7.7
7.8 mm	Metric	0.3071	7.8
7.9 mm	Metric	0.3110	7.9
5/16″	Fractional	0.3125	7.938
8 mm	Metric	0.3150	8
O	Letter	0.3160	8.026
8.1 mm	Metric	0.3189	8.1
8.2 mm	Metric	0.3228	8.2
P	Letter	0.3230	8.204
8.3 mm	Metric	0.3268	8.3
21/64″	Fractional	0.3281	8.334
8.4 mm	Metric	0.3307	8.4
Q	Letter	0.3320	8.433
8.5 mm	Metric	0.3346	8.5
8.6 mm	Metric	0.3386	8.6
R	Letter	0.3390	8.611
8.7 mm	Metric	0.3425	8.7
11/32″	Fractional	0.3438	8.731
8.8 mm	Metric	0.3465	8.8
S	Letter	0.3480	8.839
8.9 mm	Metric	0.3504	8.9
9 mm	Metric	0.3543	9
T	Letter	0.3580	9.093
9.1 mm	Metric	0.3583	9.1
23/64″	Fractional	0.3594	9.128
9.2 mm	Metric	0.3622	9.2
9.3 mm	Metric	0.3661	9.3
U	Letter	0.3680	9.347
9.4 mm	Metric	0.3701	9.4
9.5 mm	Metric	0.3740	9.5
3/8″	Fractional	0.3750	9.525
V	Letter	0.3770	9.576
9.6 mm	Metric	0.3780	9.6
9.7 mm	Metric	0.3819	9.7
9.8 mm	Metric	0.3858	9.8
W	Letter	0.3860	9.804
9.9 mm	Metric	0.3898	9.9
25/64″	Fractional	0.3906	9.922
10 mm	Metric	0.3937	10
X	Letter	0.3970	10.084
10.1 mm	Metric	0.3976	10.1
10.2 mm	Metric	0.4016	10.2
Y	Letter	0.4040	10.262
10.3 mm	Metric	0.4055	10.3
13/32″	Fractional	0.4063	10.319
10.4 mm	Metric	0.4094	10.4
Z	Letter	0.4130	10.49
10.5 mm	Metric	0.4134	10.5
10.6 mm	Metric	0.4173	10.6
10.7 mm	Metric	0.4213	10.7
27/64″	Fractional	0.4219	10.716
10.8 mm	Metric	0.4252	10.8
10.9 mm	Metric	0.4291	10.9
11 mm	Metric	0.4331	11
11.1 mm	Metric	0.4370	11.1
7/16″	Fractional	0.4375	11.112
11.2 mm	Metric	0.4409	11.2
11.3 mm	Metric	0.4449	11.3
11.4 mm	Metric	0.4488	11.4
11.5 mm	Metric	0.4528	11.5
29/64″	Fractional	0.4531	11.509
11.6 mm	Metric	0.4567	11.6
11.7 mm	Metric	0.4606	11.7
11.8 mm	Metric	0.4646	11.8
11.9 mm	Metric	0.4685	11.9
15/32″	Fractional	0.4688	11.906
12 mm	Metric	0.4724	12
12.1 mm	Metric	0.4764	12.1
12.2 mm	Metric	0.4803	12.2
12.3 mm	Metric	0.4843	12.3
31/64″	Fractional	0.4844	12.303
12.4 mm	Metric	0.4882	12.4
12.5 mm	Metric	0.4921	12.5
12.6 mm	Metric	0.4961	12.6
1/2″	Fractional	0.5000	12.7
12.7 mm	Metric	0.5000	12.7
12.8 mm	Metric	0.5039	12.8
12.9 mm	Metric	0.5079	12.9
13 mm	Metric	0.5118	13
33/64″	Fractional	0.5156	13.097
17/32″	Fractional	0.5313	13.494
13.5 mm	Metric	0.5315	13.5
35/64″	Fractional	0.5469	13.891
14 mm	Metric	0.5512	14
9/16″	Fractional	0.5625	14.287
14.5 mm	Metric	0.5709	14.5
37/64″	Fractional	0.5781	14.684
15 mm	Metric	0.5906	15
19/32″	Fractional	0.5938	15.081
39/64″	Fractional	0.6094	15.478
15.5 mm	Metric	0.6102	15.5
5/8″	Fractional	0.6250	15.875
16 mm	Metric	0.6299	16
41/64″	Fractional	0.6406	16.272
16.5 mm	Metric	0.6496	16.5
21/32″	Fractional	0.6563	16.669
17 mm	Metric	0.6693	17
43/64″	Fractional	0.6719	17.066
11/16″	Fractional	0.6875	17.462
17.5 mm	Metric	0.6890	17.5
45/64″	Fractional	0.7031	17.859
18 mm	Metric	0.7087	18
23/32″	Fractional	0.7188	18.256
18.5 mm	Metric	0.7283	18.5
47/64″	Fractional	0.7344	18.653
19 mm	Metric	0.7480	19
3/4″	Fractional	0.7500	19.05
49/64″	Fractional	0.7656	19.447
19.5 mm	Metric	0.7677	19.5
25/32″	Fractional	0.7813	19.844
20 mm	Metric	0.7874	20
51/64″	Fractional	0.7969	20.241
20.5 mm	Metric	0.8071	20.5
13/16″	Fractional	0.8125	20.637
21 mm	Metric	0.8268	21
53/64″	Fractional	0.8281	21.034
27/32″	Fractional	0.8438	21.431
55/64″	Fractional	0.8594	21.828
7/8″	Fractional	0.8750	22.225
57/64″	Fractional	0.8906	22.622
29/32″	Fractional	0.9063	23.019
59/64″	Fractional	0.9219	23.416
15/16″	Fractional	0.9375	23.813
61/64″	Fractional	0.9531	24.209
31/32″	Fractional	0.9688	24.606
63/64″	Fractional	0.9844	25.003
1″	Fractional	1.0000	25.4

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Data provenance. ASME B94.11M, Twist Drills (standard drill size series) (ASME). See all data sources.