Workshop Reference

Drill Size Conversion Chart

Search common fractional, number, letter and metric drill sizes with decimal-inch and millimetre equivalents.

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Four size systems

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Search a size, decimal inch or millimetre value. Use the result to help identify an existing drill or prepare an enquiry.

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Fractional drills conversion chart
Drill size	Decimal inch	Millimetres
1/64 in	0.0156 in	0.397 mm
1/32 in	0.0313 in	0.794 mm
3/64 in	0.0469 in	1.191 mm
1/16 in	0.0625 in	1.588 mm
5/64 in	0.0781 in	1.984 mm
3/32 in	0.0938 in	2.381 mm
7/64 in	0.1094 in	2.778 mm
1/8 in	0.1250 in	3.175 mm
9/64 in	0.1406 in	3.572 mm
5/32 in	0.1563 in	3.969 mm
11/64 in	0.1719 in	4.366 mm
3/16 in	0.1875 in	4.763 mm
13/64 in	0.2031 in	5.159 mm
7/32 in	0.2188 in	5.556 mm
15/64 in	0.2344 in	5.953 mm
1/4 in	0.2500 in	6.350 mm
17/64 in	0.2656 in	6.747 mm
9/32 in	0.2813 in	7.144 mm
19/64 in	0.2969 in	7.541 mm
5/16 in	0.3125 in	7.938 mm
21/64 in	0.3281 in	8.334 mm
11/32 in	0.3438 in	8.731 mm
23/64 in	0.3594 in	9.128 mm
3/8 in	0.3750 in	9.525 mm
25/64 in	0.3906 in	9.922 mm
13/32 in	0.4063 in	10.319 mm
27/64 in	0.4219 in	10.716 mm
7/16 in	0.4375 in	11.113 mm
29/64 in	0.4531 in	11.509 mm
15/32 in	0.4688 in	11.906 mm
31/64 in	0.4844 in	12.303 mm
1/2 in	0.5000 in	12.700 mm
33/64 in	0.5156 in	13.097 mm
17/32 in	0.5313 in	13.494 mm
35/64 in	0.5469 in	13.891 mm
9/16 in	0.5625 in	14.288 mm
37/64 in	0.5781 in	14.684 mm
19/32 in	0.5938 in	15.081 mm
39/64 in	0.6094 in	15.478 mm
5/8 in	0.6250 in	15.875 mm
41/64 in	0.6406 in	16.272 mm
21/32 in	0.6563 in	16.669 mm
43/64 in	0.6719 in	17.066 mm
11/16 in	0.6875 in	17.463 mm
45/64 in	0.7031 in	17.859 mm
23/32 in	0.7188 in	18.256 mm
47/64 in	0.7344 in	18.653 mm
3/4 in	0.7500 in	19.050 mm
49/64 in	0.7656 in	19.447 mm
25/32 in	0.7813 in	19.844 mm
51/64 in	0.7969 in	20.241 mm
13/16 in	0.8125 in	20.638 mm
53/64 in	0.8281 in	21.034 mm
27/32 in	0.8438 in	21.431 mm
55/64 in	0.8594 in	21.828 mm
7/8 in	0.8750 in	22.225 mm
57/64 in	0.8906 in	22.622 mm
29/32 in	0.9063 in	23.019 mm
59/64 in	0.9219 in	23.416 mm
15/16 in	0.9375 in	23.813 mm
61/64 in	0.9531 in	24.209 mm
31/32 in	0.9688 in	24.606 mm
63/64 in	0.9844 in	25.003 mm
1 in	1.0000 in	25.400 mm

Number drills conversion chart
Drill size	Decimal inch	Millimetres
#80	0.0135 in	0.343 mm
#79	0.0145 in	0.368 mm
#78	0.0160 in	0.406 mm
#77	0.0180 in	0.457 mm
#76	0.0200 in	0.508 mm
#75	0.0210 in	0.533 mm
#74	0.0225 in	0.572 mm
#73	0.0240 in	0.610 mm
#72	0.0250 in	0.635 mm
#71	0.0260 in	0.660 mm
#70	0.0280 in	0.711 mm
#69	0.0292 in	0.742 mm
#68	0.0310 in	0.787 mm
#67	0.0320 in	0.813 mm
#66	0.0330 in	0.838 mm
#65	0.0350 in	0.889 mm
#64	0.0360 in	0.914 mm
#63	0.0370 in	0.940 mm
#62	0.0380 in	0.965 mm
#61	0.0390 in	0.991 mm
#60	0.0400 in	1.016 mm
#59	0.0410 in	1.041 mm
#58	0.0420 in	1.067 mm
#57	0.0430 in	1.092 mm
#56	0.0465 in	1.181 mm
#55	0.0520 in	1.321 mm
#54	0.0550 in	1.397 mm
#53	0.0595 in	1.511 mm
#52	0.0635 in	1.613 mm
#51	0.0670 in	1.702 mm
#50	0.0700 in	1.778 mm
#49	0.0730 in	1.854 mm
#48	0.0760 in	1.930 mm
#47	0.0785 in	1.994 mm
#46	0.0810 in	2.057 mm
#45	0.0820 in	2.083 mm
#44	0.0860 in	2.184 mm
#43	0.0890 in	2.261 mm
#42	0.0935 in	2.375 mm
#41	0.0960 in	2.438 mm
#40	0.0980 in	2.489 mm
#39	0.0995 in	2.527 mm
#38	0.1015 in	2.578 mm
#37	0.1040 in	2.642 mm
#36	0.1065 in	2.705 mm
#35	0.1100 in	2.794 mm
#34	0.1110 in	2.819 mm
#33	0.1130 in	2.870 mm
#32	0.1160 in	2.946 mm
#31	0.1200 in	3.048 mm
#30	0.1285 in	3.264 mm
#29	0.1360 in	3.454 mm
#28	0.1405 in	3.569 mm
#27	0.1440 in	3.658 mm
#26	0.1470 in	3.734 mm
#25	0.1495 in	3.797 mm
#24	0.1520 in	3.861 mm
#23	0.1540 in	3.912 mm
#22	0.1570 in	3.988 mm
#21	0.1590 in	4.039 mm
#20	0.1610 in	4.089 mm
#19	0.1660 in	4.216 mm
#18	0.1695 in	4.305 mm
#17	0.1730 in	4.394 mm
#16	0.1770 in	4.496 mm
#15	0.1800 in	4.572 mm
#14	0.1820 in	4.623 mm
#13	0.1850 in	4.699 mm
#12	0.1890 in	4.801 mm
#11	0.1910 in	4.851 mm
#10	0.1935 in	4.915 mm
#9	0.1960 in	4.978 mm
#8	0.1990 in	5.055 mm
#7	0.2010 in	5.105 mm
#6	0.2040 in	5.182 mm
#5	0.2055 in	5.220 mm
#4	0.2090 in	5.309 mm
#3	0.2130 in	5.410 mm
#2	0.2210 in	5.613 mm
#1	0.2280 in	5.791 mm

Letter drills conversion chart
Drill size	Decimal inch	Millimetres
A	0.2340 in	5.944 mm
B	0.2380 in	6.045 mm
C	0.2420 in	6.147 mm
D	0.2460 in	6.248 mm
E	0.2500 in	6.350 mm
F	0.2570 in	6.528 mm
G	0.2610 in	6.629 mm
H	0.2660 in	6.756 mm
I	0.2720 in	6.909 mm
J	0.2770 in	7.036 mm
K	0.2810 in	7.137 mm
L	0.2900 in	7.366 mm
M	0.2950 in	7.493 mm
N	0.3020 in	7.671 mm
O	0.3160 in	8.026 mm
P	0.3230 in	8.204 mm
Q	0.3320 in	8.433 mm
R	0.3390 in	8.611 mm
S	0.3480 in	8.839 mm
T	0.3580 in	9.093 mm
U	0.3680 in	9.347 mm
V	0.3770 in	9.576 mm
W	0.3860 in	9.804 mm
X	0.3970 in	10.084 mm
Y	0.4040 in	10.262 mm
Z	0.4130 in	10.490 mm

Metric drills conversion chart
Drill size	Decimal inch	Millimetres
0.5 mm	0.0197 in	0.500 mm
0.6 mm	0.0236 in	0.600 mm
0.7 mm	0.0276 in	0.700 mm
0.8 mm	0.0315 in	0.800 mm
0.9 mm	0.0354 in	0.900 mm
1.0 mm	0.0394 in	1.000 mm
1.1 mm	0.0433 in	1.100 mm
1.2 mm	0.0472 in	1.200 mm
1.3 mm	0.0512 in	1.300 mm
1.4 mm	0.0551 in	1.400 mm
1.5 mm	0.0591 in	1.500 mm
1.6 mm	0.0630 in	1.600 mm
1.7 mm	0.0669 in	1.700 mm
1.8 mm	0.0709 in	1.800 mm
1.9 mm	0.0748 in	1.900 mm
2.0 mm	0.0787 in	2.000 mm
2.1 mm	0.0827 in	2.100 mm
2.2 mm	0.0866 in	2.200 mm
2.3 mm	0.0906 in	2.300 mm
2.4 mm	0.0945 in	2.400 mm
2.5 mm	0.0984 in	2.500 mm
2.6 mm	0.1024 in	2.600 mm
2.7 mm	0.1063 in	2.700 mm
2.8 mm	0.1102 in	2.800 mm
2.9 mm	0.1142 in	2.900 mm
3.0 mm	0.1181 in	3.000 mm
3.1 mm	0.1220 in	3.100 mm
3.2 mm	0.1260 in	3.200 mm
3.3 mm	0.1299 in	3.300 mm
3.4 mm	0.1339 in	3.400 mm
3.5 mm	0.1378 in	3.500 mm
3.6 mm	0.1417 in	3.600 mm
3.7 mm	0.1457 in	3.700 mm
3.8 mm	0.1496 in	3.800 mm
3.9 mm	0.1535 in	3.900 mm
4.0 mm	0.1575 in	4.000 mm
4.1 mm	0.1614 in	4.100 mm
4.2 mm	0.1654 in	4.200 mm
4.3 mm	0.1693 in	4.300 mm
4.4 mm	0.1732 in	4.400 mm
4.5 mm	0.1772 in	4.500 mm
4.6 mm	0.1811 in	4.600 mm
4.7 mm	0.1850 in	4.700 mm
4.8 mm	0.1890 in	4.800 mm
4.9 mm	0.1929 in	4.900 mm
5.0 mm	0.1969 in	5.000 mm
5.1 mm	0.2008 in	5.100 mm
5.2 mm	0.2047 in	5.200 mm
5.3 mm	0.2087 in	5.300 mm
5.4 mm	0.2126 in	5.400 mm
5.5 mm	0.2165 in	5.500 mm
5.6 mm	0.2205 in	5.600 mm
5.7 mm	0.2244 in	5.700 mm
5.8 mm	0.2283 in	5.800 mm
5.9 mm	0.2323 in	5.900 mm
6.0 mm	0.2362 in	6.000 mm
6.1 mm	0.2402 in	6.100 mm
6.2 mm	0.2441 in	6.200 mm
6.3 mm	0.2480 in	6.300 mm
6.4 mm	0.2520 in	6.400 mm
6.5 mm	0.2559 in	6.500 mm
6.6 mm	0.2598 in	6.600 mm
6.7 mm	0.2638 in	6.700 mm
6.8 mm	0.2677 in	6.800 mm
6.9 mm	0.2717 in	6.900 mm
7.0 mm	0.2756 in	7.000 mm
7.1 mm	0.2795 in	7.100 mm
7.2 mm	0.2835 in	7.200 mm
7.3 mm	0.2874 in	7.300 mm
7.4 mm	0.2913 in	7.400 mm
7.5 mm	0.2953 in	7.500 mm
7.6 mm	0.2992 in	7.600 mm
7.7 mm	0.3031 in	7.700 mm
7.8 mm	0.3071 in	7.800 mm
7.9 mm	0.3110 in	7.900 mm
8.0 mm	0.3150 in	8.000 mm
8.1 mm	0.3189 in	8.100 mm
8.2 mm	0.3228 in	8.200 mm
8.3 mm	0.3268 in	8.300 mm
8.4 mm	0.3307 in	8.400 mm
8.5 mm	0.3346 in	8.500 mm
8.6 mm	0.3386 in	8.600 mm
8.7 mm	0.3425 in	8.700 mm
8.8 mm	0.3465 in	8.800 mm
8.9 mm	0.3504 in	8.900 mm
9.0 mm	0.3543 in	9.000 mm
9.1 mm	0.3583 in	9.100 mm
9.2 mm	0.3622 in	9.200 mm
9.3 mm	0.3661 in	9.300 mm
9.4 mm	0.3701 in	9.400 mm
9.5 mm	0.3740 in	9.500 mm
9.6 mm	0.3780 in	9.600 mm
9.7 mm	0.3819 in	9.700 mm
9.8 mm	0.3858 in	9.800 mm
9.9 mm	0.3898 in	9.900 mm
10.0 mm	0.3937 in	10.000 mm
10.1 mm	0.3976 in	10.100 mm
10.2 mm	0.4016 in	10.200 mm
10.3 mm	0.4055 in	10.300 mm
10.4 mm	0.4094 in	10.400 mm
10.5 mm	0.4134 in	10.500 mm
10.6 mm	0.4173 in	10.600 mm
10.7 mm	0.4213 in	10.700 mm
10.8 mm	0.4252 in	10.800 mm
10.9 mm	0.4291 in	10.900 mm
11.0 mm	0.4331 in	11.000 mm
11.1 mm	0.4370 in	11.100 mm
11.2 mm	0.4409 in	11.200 mm
11.3 mm	0.4449 in	11.300 mm
11.4 mm	0.4488 in	11.400 mm
11.5 mm	0.4528 in	11.500 mm
11.6 mm	0.4567 in	11.600 mm
11.7 mm	0.4606 in	11.700 mm
11.8 mm	0.4646 in	11.800 mm
11.9 mm	0.4685 in	11.900 mm
12.0 mm	0.4724 in	12.000 mm
12.1 mm	0.4764 in	12.100 mm
12.2 mm	0.4803 in	12.200 mm
12.3 mm	0.4843 in	12.300 mm
12.4 mm	0.4882 in	12.400 mm
12.5 mm	0.4921 in	12.500 mm
12.6 mm	0.4961 in	12.600 mm
12.7 mm	0.5000 in	12.700 mm
12.8 mm	0.5039 in	12.800 mm
12.9 mm	0.5079 in	12.900 mm
13.0 mm	0.5118 in	13.000 mm
13.1 mm	0.5157 in	13.100 mm
13.2 mm	0.5197 in	13.200 mm
13.3 mm	0.5236 in	13.300 mm
13.4 mm	0.5276 in	13.400 mm
13.5 mm	0.5315 in	13.500 mm
13.6 mm	0.5354 in	13.600 mm
13.7 mm	0.5394 in	13.700 mm
13.8 mm	0.5433 in	13.800 mm
13.9 mm	0.5472 in	13.900 mm
14.0 mm	0.5512 in	14.000 mm
14.1 mm	0.5551 in	14.100 mm
14.2 mm	0.5591 in	14.200 mm
14.3 mm	0.5630 in	14.300 mm
14.4 mm	0.5669 in	14.400 mm
14.5 mm	0.5709 in	14.500 mm
14.6 mm	0.5748 in	14.600 mm
14.7 mm	0.5787 in	14.700 mm
14.8 mm	0.5827 in	14.800 mm
14.9 mm	0.5866 in	14.900 mm
15.0 mm	0.5906 in	15.000 mm
15.1 mm	0.5945 in	15.100 mm
15.2 mm	0.5984 in	15.200 mm
15.3 mm	0.6024 in	15.300 mm
15.4 mm	0.6063 in	15.400 mm
15.5 mm	0.6102 in	15.500 mm
15.6 mm	0.6142 in	15.600 mm
15.7 mm	0.6181 in	15.700 mm
15.8 mm	0.6220 in	15.800 mm
15.9 mm	0.6260 in	15.900 mm
16.0 mm	0.6299 in	16.000 mm
16.1 mm	0.6339 in	16.100 mm
16.2 mm	0.6378 in	16.200 mm
16.3 mm	0.6417 in	16.300 mm
16.4 mm	0.6457 in	16.400 mm
16.5 mm	0.6496 in	16.500 mm
16.6 mm	0.6535 in	16.600 mm
16.7 mm	0.6575 in	16.700 mm
16.8 mm	0.6614 in	16.800 mm
16.9 mm	0.6654 in	16.900 mm
17.0 mm	0.6693 in	17.000 mm
17.1 mm	0.6732 in	17.100 mm
17.2 mm	0.6772 in	17.200 mm
17.3 mm	0.6811 in	17.300 mm
17.4 mm	0.6850 in	17.400 mm
17.5 mm	0.6890 in	17.500 mm
17.6 mm	0.6929 in	17.600 mm
17.7 mm	0.6969 in	17.700 mm
17.8 mm	0.7008 in	17.800 mm
17.9 mm	0.7047 in	17.900 mm
18.0 mm	0.7087 in	18.000 mm
18.1 mm	0.7126 in	18.100 mm
18.2 mm	0.7165 in	18.200 mm
18.3 mm	0.7205 in	18.300 mm
18.4 mm	0.7244 in	18.400 mm
18.5 mm	0.7283 in	18.500 mm
18.6 mm	0.7323 in	18.600 mm
18.7 mm	0.7362 in	18.700 mm
18.8 mm	0.7402 in	18.800 mm
18.9 mm	0.7441 in	18.900 mm
19.0 mm	0.7480 in	19.000 mm
19.1 mm	0.7520 in	19.100 mm
19.2 mm	0.7559 in	19.200 mm
19.3 mm	0.7598 in	19.300 mm
19.4 mm	0.7638 in	19.400 mm
19.5 mm	0.7677 in	19.500 mm
19.6 mm	0.7717 in	19.600 mm
19.7 mm	0.7756 in	19.700 mm
19.8 mm	0.7795 in	19.800 mm
19.9 mm	0.7835 in	19.900 mm
20.0 mm	0.7874 in	20.000 mm
20.1 mm	0.7913 in	20.100 mm
20.2 mm	0.7953 in	20.200 mm
20.3 mm	0.7992 in	20.300 mm
20.4 mm	0.8031 in	20.400 mm
20.5 mm	0.8071 in	20.500 mm
20.6 mm	0.8110 in	20.600 mm
20.7 mm	0.8150 in	20.700 mm
20.8 mm	0.8189 in	20.800 mm
20.9 mm	0.8228 in	20.900 mm
21.0 mm	0.8268 in	21.000 mm
21.1 mm	0.8307 in	21.100 mm
21.2 mm	0.8346 in	21.200 mm
21.3 mm	0.8386 in	21.300 mm
21.4 mm	0.8425 in	21.400 mm
21.5 mm	0.8465 in	21.500 mm
21.6 mm	0.8504 in	21.600 mm
21.7 mm	0.8543 in	21.700 mm
21.8 mm	0.8583 in	21.800 mm
21.9 mm	0.8622 in	21.900 mm
22.0 mm	0.8661 in	22.000 mm
22.1 mm	0.8701 in	22.100 mm
22.2 mm	0.8740 in	22.200 mm
22.3 mm	0.8780 in	22.300 mm
22.4 mm	0.8819 in	22.400 mm
22.5 mm	0.8858 in	22.500 mm
22.6 mm	0.8898 in	22.600 mm
22.7 mm	0.8937 in	22.700 mm
22.8 mm	0.8976 in	22.800 mm
22.9 mm	0.9016 in	22.900 mm
23.0 mm	0.9055 in	23.000 mm
23.1 mm	0.9094 in	23.100 mm
23.2 mm	0.9134 in	23.200 mm
23.3 mm	0.9173 in	23.300 mm
23.4 mm	0.9213 in	23.400 mm
23.5 mm	0.9252 in	23.500 mm
23.6 mm	0.9291 in	23.600 mm
23.7 mm	0.9331 in	23.700 mm
23.8 mm	0.9370 in	23.800 mm
23.9 mm	0.9409 in	23.900 mm
24.0 mm	0.9449 in	24.000 mm
24.1 mm	0.9488 in	24.100 mm
24.2 mm	0.9528 in	24.200 mm
24.3 mm	0.9567 in	24.300 mm
24.4 mm	0.9606 in	24.400 mm
24.5 mm	0.9646 in	24.500 mm
24.6 mm	0.9685 in	24.600 mm
24.7 mm	0.9724 in	24.700 mm
24.8 mm	0.9764 in	24.800 mm
24.9 mm	0.9803 in	24.900 mm
25.0 mm	0.9843 in	25.000 mm

Reference and identification aid

Nominal conversions are rounded for display. Verify the required diameter, tolerance, drill standard, shank type, length, material and application before ordering or machining.

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