Drill Size Chart

by · February 16, 2018

This chart gives the decimal equivalent of fractional, number, letter, and metric sizes in order of increasing size.

Reference Only. See Terms of Use.

FRACTION # SIZE LETTER METRIC DECIMAL INCHES
#80 0.0135
#79 0.0145
1/64 0.0156
#78 0.0160
#77 0.0180
0.5mm 0.0197
#76 0.0200
#75 0.0210
#74 0.0225
#73 0.0240
#72 0.0250
#71 0.0260
#70 0.0280
#69 0.0292
0.75mm 0.0295
#68 0.0310
1/32 0.0312
#67 0.0320
#66 0.0330
#65 0.0350
#64 0.0360
#63 0.0370
#62 0.0380
#61 0.0390
1mm 0.0394
#60 0.0400
#59 0.0410
#58 0.0420
#57 0.0430
#56 0.0465
3/64 0.0469
1.25mm 0.0492
#55 0.0520
#54 0.0550
1.5mm 0.0591
#53 0.0595
1/16 0.0625
#52 0.0635
#51 0.0670
1.75mm 0.0689
#50 0.0700
#49 0.0730
#48 0.0760
5/64 0.0781
#47 0.0785
2mm 0.0787
#46 0.0810
#45 0.0820
#44 0.0860
2.25mm 0.0886
#43 0.0890
#42 0.0935
3/32 0.0938
#41 0.0960
#40 0.0980
2.5mm 0.0984
#39 0.0995
#38 0.1015
#37 0.1040
#36 0.1065
2.75mm 0.1083
7/64 0.1094
#35 0.1100
#34 0.1110
#33 0.1130
#32 0.1160
3mm 0.1181
#31 0.1200
1/8 0.1250
3.25mm 0.1280
#30 0.1285
#29 0.1360
3.5mm 0.1378
#28 0.1405
9/64 0.1406
#27 0.1440
#26 0.1470
3.75mm 0.1476
#25 0.1495
#24 0.1520
#23 0.1540
5/32 0.1562
#22 0.1570
4mm 0.1575
#21 0.1590
#20 0.1610
#19 0.1660
4.25mm 0.1673
#18 0.1695
11/64 0.1719
#17 0.1730
#16 0.1770
4.5mm 0.1772
#15 0.1800
#14 0.1820
#13 0.1850
4.75mm 0.1870
3/16 0.1875
#12 0.1890
#11 0.1910
#10 0.1935
#9 0.1960
5mm 0.1969
#8 0.1990
#7 0.2010
13/64 0.2031
#6 0.2040
#5 0.2055
5.25mm 0.2067
#4 0.2090
#3 0.2130
5.5mm 0.2165
7/32 0.2188
#2 0.2210
5.75mm 0.2264
#1 0.2280
A 0.2340
15/64 0.2344
6mm 0.2362
B 0.2380
C 0.2420
D 0.2460
6.25mm 0.2461
1/4 E 0.2500
6.5mm 0.2559
F 0.2570
G 0.2610
17/64 0.2656
6.75mm 0.2657
H 0.2660
I 0.2720
7mm 0.2756
J 0.2770
K 0.2810
9/32 0.2812
7.25mm 0.2854
L 0.2900
M 0.2950
7.5mm 0.2953
19/64 0.2969
N 0.3020
7.75mm 0.3051
5/16 0.3125
8mm 0.3150
O 0.3160
P 0.3230
8.25mm 0.3248
21/64 0.3281
Q 0.3320
8.5mm 0.3346
R 0.3390
11/32 0.3438
8.75mm 0.3445
S 0.3480
9mm 0.3543
T 0.3580
23/64 0.3594
9.25mm 0.3642
U 0.3680
9.5mm 0.3740
3/8 0.3750
V 0.3770
9.75mm 0.3839
W 0.3860
25/64 0.3906
10mm 0.3937
X 0.3970
Y 0.4040
13/32 0.4063
Z 0.4130
10.5mm 0.4134
27/64 0.4219
11mm 0.4331
7/16 0.4375
11.5mm 0.4528
29/64 0.4531
15/32 0.4688
12mm 0.4724
31/64 0.4844
12.5mm 0.4921
1/2 0.5000
13mm 0.5118
33/64 0.5156
17/32 0.5312
13.5mm 0.5315
35/64 0.5469
14mm 0.5512
9/16 0.5625
14.5mm 0.5709
37/64 0.5781
15mm 0.5906
19/32 0.5938
39/64 0.6094
15.5mm 0.6102
5/8 0.6250
16mm 0.6299
41/64 0.6406
16.5mm 0.6496
21/32 0.6562
17mm 0.6693
43/64 0.6719
11/16 0.6875
17.5mm 0.6890
45/64 0.7031
18mm 0.7087
23/32 0.7188
18.5mm 0.7283
47/64 0.7344
19mm 0.7480
3/4 0.7500
49/64 0.7656
19.5mm 0.7677
25/32 0.7813
20mm 0.7874
Ā 51/64 0.7969
20.5mm 0.8071
13/16 0.8125
21mm 0.8268
53/64 0.8281
27/32 0.8438
21.5mm 0.8465
55/64 0.8594
22mm 0.8661
7/8 0.8750
22.5mm 0.8858
57/64 0.8906
23mm 0.9055
29/32 0.9062
59/64 0.9219
23.5mm 0.9252
15/16 0.9375
24mm 0.9449
61/64 0.9531
24.5mm 0.9646
31/32 0.9688
25mm 0.9843
63/64 0.9844
1 inch 1.0000

For design, see:

  • ASME B94.11 ā€“ Twist Drills
    • This Standard covers nomenclature, definitions, sizes and tolerances of High Speed Steel, Straight and Taper Shank Drills, and Combined Drills and Countersinks, Plain and Bell Type. It covers both inch and metric size drills.
  • ASME B18.2.8 ā€“ Clearance holes for bolts, screws and studs
    • This Standard covers the recommended clearance hole sizes for #0 through 1.5 in. and M1.6 through M100 metric fasteners in three classes of clearance using a close-, normal-, and loose-fit category.

Tags: