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Drill Bit Size Chart | Drill Size Chart in Fractional-Inch, Metric


Power Tools help you to cut, make holes, hammer and many other tasks with very little effort and produce pretty accurate and precise results. Of all the power tools, the Drill is perhaps the most commonly used tool by residential users, DIYers, woodworking, automobile, construction and electrical workshops. Depending on the type of materials you work with, you will need a variety of Drill Bits for the job. Apart from the right type of Drill Bit, you also need the correct Drill Bit Size. With the knowledge of Drill Bit Sizes, you can select the right drill bit or opt for a close alternative. So, in this guide, let us get to know different Drill sizes with the help of Drill Bit Size Chart or Drill Size Chart.

A Brief Note on Drills and Drill Bits

An electric drill is perhaps the most common and frequently used power tool. The main job of a drill is to make holes in wood, metal, masonry and other materials. Cordless Electric Drills are becoming extremely popular in both the DIY community as well as with the professional usage.

The following image shows a typical cordless electric drill along with all its important parts. A drill usually has a handle with good grip to hold the drill, a rechargeable and removable battery, a trigger switch and a chuck. Speaking of chuck, it has two parts: metal jaws that hold shank of a drill bit and a plastic part that rotates to tighten or loosen the jaws.

Apart from these, a drill also has a forward/reverse switch, a torque collar to manually adjust the torque.

Coming to the Drill Bits, they are the main rotating parts that make the holes in wood (or other materials). Depending on the type of material we are working on i.e., wood, metal, masonry etc., there are different type of drill bits.

Types of Drill Bits

Before diving into Drill Sizes and Drill Bit Size Chart, let us quickly take a look at some of the popular types of drill bits.

  • Twist Bit: This is perhaps the largest produced drill bit today. These bits come in almost all drill bits kits and you can use them to make holes in wood, metal, plastic, etc. Coming to sizes, twist bits are available from 1/16 inch to 1/2 inch.
  • Spade Bit: This bit has a flat square shape with a point on the end to make wider holes particularly in wood. The point end centers the bit for the hole and the paddle shape part will follow to make a wider diameter.
  • Wood-Spur Bit: Also known as Brad Point Bit, is a type of twist bit that is primarily used with wood. Unlike conventional twist bits, which have a flat end, the Wood-Spur bit has a pointed end, just like a spade bit. Hence, we can consider a wood-spur bit as a cross between twist bit and a spade bit.
  • Masonry Bit: As the name suggests, we use masonry bits to make holes on concrete, bricks, cement and stone. The tip of these bits is wide and is usually made up of tungsten carbide, which is known for its strength.
  • Forstner Bit: We use these bits primarily with drill presses rather than handheld drills. This bit also helps you make wider holes, just like spade bits. But unlike spade bits, Forstner bit make flat bottoms.

Drill Bit Sizes

Just like other gauges, the Drill Bit Sizes are also defined as per different international standards. In the U.S., Fractional Inch and Wire Gauge & Letter are very common whereas in the rest of the World, the metric drill bit sizes are predominant.

Defined in the ANSI B94.11M-1979 Standards, the fractional inch drill bit sizes start from 1/64 inch and scale up all the way to 1inch with 1/64inch increments.

The Number & Letter Gauge drill bit sizes are very similar to American Wire Gauge (only in the representation but not the actual gauge numbers). The largest gauge number (for example #107) indicates the smallest drill bit size and as the numbers decrease (#1), the drill bit size also increases.

After #1, the gauge number end and letters start with ‘A’ all the way up to ‘Z’. Here, A is next largest drill bit size then #1 and the pattern continues with Z being the largest.

Metric Drill Sizes are straightforward representation with the drill size (equivalent to gauge number) is same as the diameter of the drill size.

Drill Bit Size Gauge

If you are familiar with the wire gauge (the circular tool that helps you identify the diameter of a wire), there is also a Drill Size Gauge or Drill Bit Size Gauge. It is usually a rectangular plate with several holes corresponding to different drill sizes. The following image shows a typical drill bit gauge (not to scale).

Image

You can use such device to easily identify the gauge of your drill bit.

Drill Bit Size Chart

Let us now see the Drill Bit Size Chart. Since there are different standards and representations, we will also have multiple charts, with chart having the diameter both in inches and millimeters.

Drill Size Chart – Fractional Sizes

Drill Size

(in)

Diameter Drill Size

(in)

 

Diameter
Inches (in) Millimeters (mm) Inches (in) Millimeters (mm)
1/64 0.0156 0.3969 49/64 0.7656 19.4469
1/32 0.0313 0.7938 25/32 0.7813 19.8438
3/64 0.0469 1.1906 51/64 0.7969 20.2406
1/16 0.0625 1.5875 13/16 0.8125 20.6375
5/64 0.0781 1.9844 53/64 0.8281 21.0344
3/32 0.0938 2.3813 27/32 0.8438 21.4313
7/64 0.1094 2.7781 55/64 0.8594 21.8281
1/8 0.125 3.175 7/8 0.875 22.225
9/64 0.1406 3.5719 57/64 0.8906 22.6219
5/32 0.1563 3.9688 29/32 0.9063 23.0188
11/64 0.1719 4.3656 59/64 0.9219 23.4156
3/16 0.1875 4.7625 15/16 0.9375 23.8125
13/64 0.2031 5.1594 61/64 0.9531 24.2094
7/32 0.2188 5.5563 31/32 0.9688 24.6063
15/64 0.2344 5.9531 63/64 0.9844 25.0031
1/4 0.25 6.35 1 1 25.4
17/64 0.2656 6.7469 1-1/64 1.0156 25.7969
9/32 0.2813 7.1438 1-1/32 1.0313 26.1938
19/64 0.2969 7.5406 1-3/64 1.0469 26.5906
5/16 0.3125 7.9375 1-1/16 1.0625 26.9875
21/64 0.3281 8.3344 1-5/64 1.0781 27.3844
11/32 0.3438 8.7313 1-3/32 1.0938 27.7813
23/64 0.3594 9.1281 1-7/64 1.1094 28.1781
3/8 0.375 9.525 1-1/8 1.125 28.575
25/64 0.3906 9.9219 1-9/64 1.1406 28.9719
13/32 0.4063 10.3188 1-5/32 1.1563 29.3688
27/64 0.4219 10.7156 1-1/64 1.1719 29.7656
7/16 0.4375 11.1125 1-3/16 1.1875 30.1625
29/64 0.4531 11.5094 1-13/64 1.2031 30.5594
15/32 0.4688 11.9063 1-7/32 1.2188 30.9563
31/64 0.4844 12.3031 1-15/64 1.2344 31.3531
1/2 0.5 12.7 1-1/4 1.25 31.75
33/64 0.5156 13.0969 1-17/64 1.2656 31.1469
17/32 0.5313 13.4938 1-9/32 1.2813 32.5438
35/64 0.5469 13.8906 1-19/64 1.2969 32.9406
9/16 0.5625 14.2875 1-5/16 1.3125 33.3375
37/64 0.5781 14.6844 1-21/64 1.3281 33.7344
19/32 0.5938 15.0813 1-11/32 1.3438 34.1313
39/64 0.6094 15.4781 1-23/64 1.3594 34.5281
5/8 0.625 15.875 1-3/8 1.375 34.925
41/64 0.6406 16.2719 1-25/64 1.3906 35.3219
21/32 0.6563 16.6688 1-13/32 1.4063 35.7188
43/64 0.6719 17.0656 1-27/64 1.4219 36.1156
11/16 0.6875 17.4625 1-7/16 1.4375 36.5125
45/64 0.7013 17.8594 1-29/64 1.4531 36.9094
23/32 0.7188 18.2563 1-15/32 1.4688 37.3063
47/64 0.7344 18.6531 1-31/64 1.4844 37.7031
3/4 0.75 19.05 1-1/2 1.5 38.1

Drill Size Chart – Wire Gauge and Letter

Drill Size Diameter Drill Size Diameter
Inches (in) Millimeters (mm) Inches (in) Millimeters (mm)
#107 0.0019 0.0483 #40 0.0980 2.4892
#106 0.0023 0.0584 #39 0.0995 2.5273
#105 0.0027 0.0686 #38 0.1015 2.5781
#104 0.0031 0.0787 #37 0.1040 2.6416
#103 0.0035 0.0889 #36 0.1065 2.7051
#102 0.0039 0.0991 #35 0.1100 2.7940
#101 0.0043 0.1092 #34 0.1110 2.8194
#100 0.0047 0.1194 #33 0.1130 2.8702
#99 0.0051 0.1295 #32 0.1160 2.9464
#98 0.0055 0.1397 #31 0.1200 3.0480
#97 0.0059 0.1499 #30 0.1285 3.2639
#96 0.0063 0.1600 #29 0.1360 3.4544
#95 0.0067 0.1702 #28 0.1405 3.5687
#94 0.0071 0.1803 #27 0.1440 3.6576
#93 0.0075 0.1905 #26 0.1470 3.7338
#92 0.0079 0.2007 #25 0.1495 3.7973
#91 0.0083 0.2108 #24 0.1520 3.8608
#90 0.0087 0.2210 #23 0.1540 3.9116
#89 0.0091 0.2311 #22 0.1570 3.9878
#88 0.0095 0.2413 #21 0.1590 4.0386
#87 0.0100 0.2540 #20 0.1610 4.0894
#86 0.0105 0.2667 #19 0.1660 4.2164
#85 0.0110 0.2794 #18 0.1695 4.3053
#84 0.0115 0.2921 #17 0.1730 4.3942
#83 0.0120 0.3048 #16 0.1770 4.4958
#82 0.0125 0.3175 #15 0.1800 4.5720
#81 0.0130 0.3302 #14 0.1820 4.6228
#80 0.0135 0.3429 #13 0.1850 4.6990
#79 0.0145 0.3680 #12 0.1890 4.8006
#78 0.0160 0.4064 #11 0.1910 4.8514
#77 0.0180 0.4572 #10 0.1935 4.9149
#76 0.0200 0.5080 #9 0.1960 4.9784
#75 0.0210 0.5334 #8 0.1990 5.0546
#74 0.0225 0.5715 #7 0.2010 5.1054
#73 0.0240 0.6096 #6 0.2040 5.1816
#72 0.0250 0.6350 #5 0.2055 5.2197
#71 0.0260 0.6604 #4 0.2090 5.3086
#70 0.0280 0.7112 #3 0.2130 5.4102
#69 0.0292 0.7417 #2 0.2210 5.6134
#68 0.0310 0.7874 #1 0.2280 5.7912
#67 0.0320 0.8128 A 0.2340 5.9436
#66 0.0330 0.8382 B 0.2380 6.0452
#65 0.0350 0.8890 C 0.2420 6.1468
#64 0.0360 0.9144 D 0.2460 6.2484
#63 0.0370 0.9398 E 0.2500 6.3500
#62 0.0380 0.9652 F 0.2570 6.5278
#61 0.0390 0.9906 G 0.2610 6.6294
#60 0.0400 1.0160 H 0.2660 6.7564
#59 0.0410 1.0414 I 0.2720 6.9088
#58 0.0420 1.0668 J 0.2770 7.0358
#57 0.0430 1.0922 K 0.2810 7.1374
#56 0.0465 1.1811 L 0.2900 7.3660
#55 0.0520 1.3208 M 0.2950 7.4930
#54 0.0550 1.3970 N 0.3020 7.6708
#53 0.0595 1.5113 O 0.3160 8.0264
#52 0.0635 1.6129 P 0.3230 8.2042
#51 0.0670 1.7018 Q 0.3320 8.4328
#50 0.0700 1.7780 R 0.3390 8.6106
#49 0.0730 1.8542 S 0.3480 8.8392
#48 0.0760 1.9304 T 0.3580 9.0932
#47 0.0785 1.9939 U 0.3680 9.3472
#46 0.0810 2.0574 V 0.3770 9.5758
#45 0.0820 2.0828 W 0.3860 9.8044
#44 0.0860 2.1844 X 0.3970 10.0838
#43 0.0890 2.2606 Y 0.4040 10.2616
#42 0.0935 2.3749 Z 0.4130 10.4902
#41 0.0960 2.4384

Drill Size Chart – Metric Sizes

Drill Size (mm) Diameter Drill Size (mm) Diameter
Inches (in) Millimeters (mm) Inches (in) Millimeters (mm)
0.05 0.0020 0.05 7.9 0.3110 7.9
0.1 0.0039 0.1 8 0.3150 8
0.2 0.0079 0.2 8.1 0.3189 8.1
0.3 0.0118 0.3 8.2 0.3228 8.2
0.4 0.0158 0.4 8.3 0.3268 8.3
0.5 0.0197 0.5 8.4 0.3307 8.4
0.6 0.0236 0.6 8.5 0.3347 8.5
0.7 0.0276 0.7 8.6 0.3386 8.6
0.8 0.0315 0.8 8.7 0.3425 8.7
0.9 0.0354 0.9 8.8 0.3465 8.8
1 0.0394 1 8.9 0.3504 8.9
1.1 0.0433 1.1 9 0.3543 9
1.2 0.0472 1.2 9.1 0.3583 9.1
1.3 0.0512 1.3 9.2 0.3622 9.2
1.4 0.0551 1.4 9.3 0.3661 9.3
1.5 0.0591 1.5 9.4 0.3701 9.4
1.6 0.0630 1.6 9.5 0.3740 9.5
1.7 0.0669 1.7 9.6 0.3780 9.6
1.8 0.0709 1.8 9.7 0.3819 9.7
1.9 0.0748 1.9 9.8 0.3858 9.8
2 0.0787 2 9.9 0.3898 9.9
2.1 0.0827 2.1 10 0.3937 10
2.2 0.0866 2.2 10.5 0.4134 10.5
2.3 0.0906 2.3 11 0.4331 11
2.4 0.0945 2.4 11.5 0.4528 11.5
2.5 0.0984 2.5 12 0.4724 12
2.6 0.1024 2.6 12.5 0.4921 12.5
2.7 0.1063 2.7 13 0.5118 13
2.8 0.1102 2.8 13.5 0.5315 13.5
2.9 0.1142 2.9 14 0.5512 14
3 0.1181 3 14.5 0.5709 14.5
3.1 0.1221 3.1 15 0.5906 15
3.2 0.1260 3.2 15.5 0.6102 15.5
3.3 0.1299 3.3 16 0.6299 16
3.4 0.1339 3.4 16.5 0.6496 16.5
3.5 0.1378 3.5 17 0.6693 17
3.6 0.1417 3.6 17.5 0.6890 17.5
3.7 0.1457 3.7 18 0.7087 18
3.8 0.1496 3.8 18.5 0.7284 18.5
3.9 0.1535 3.9 19 0.7480 19
4 0.1575 4 19.5 0.7677 19.5
4.1 0.1614 4.1 20 0.7874 20
4.2 0.1654 4.2 20.5 0.8071 20.5
4.3 0.1693 4.3 21 0.8268 21
4.4 0.1732 4.4 21.5 0.8465 21.5
4.5 0.1772 4.5 22 0.8661 22
4.6 0.1811 4.6 22.5 0.8858 22.5
4.7 0.1850 4.7 23 0.9055 23
4.8 0.1890 4.8 23.5 0.9252 23.5
4.9 0.1929 4.9 24 0.9449 24
5 0.1969 5 24.5 0.9646 24.5
5.1 0.2008 5.1 25 0.9843 25
5.2 0.2047 5.2 25.5 1.0039 25.5
5.3 0.2087 5.3 26 1.0236 26
5.4 0.2126 5.4 26.5 1.0433 26.5
5.5 0.2165 5.5 27 1.0630 27
5.6 0.2205 5.6 27.5 1.0827 27.5
5.7 0.2244 5.7 28 1.1024 28
5.8 0.2284 5.8 28.5 1.1221 28.5
5.9 0.2323 5.9 29 1.1417 29
6 0.2362 6 29.5 1.1614 29.5
6.1 0.2402 6.1 30 1.1811 30
6.2 0.2441 6.2 30.5 1.2008 30.5
6.3 0.2480 6.3 31 1.2205 31
6.4 0.2520 6.4 31 1.2402 31
6.5 0.2559 6.5 32 1.2598 32
6.6 0.2598 6.6 32 1.2795 32
6.7 0.2638 6.7 33 1.2992 33
6.8 0.2677 6.8 33 1.3189 33
6.9 0.2717 6.9 34 1.3386 34
7 0.2756 7 34 1.3583 34
7.1 0.2795 7.1 35 1.3780 35
7.2 0.2835 7.2 35 1.3976 35
7.3 0.2874 7.3 36 1.4173 36
7.4 0.2913 7.4 36 1.4370 36
7.5 0.2953 7.5 37 1.4567 37
7.6 0.2992 7.6 37 1.4764 37
7.7 0.3032 7.7 38 1.4961 38
7.8 0.3071 7.8

Conclusion

Drill Bits are an important tool as they are the main part of a Drill that make the hole. Different materials need different types of drill bits. Coming to the Drill Bit Sizes, these are the diameters of holes that we want to make and are represented as gauge numbers, fractional inches or just straight forward millimeters. We learned the importance of drill bits, types of drill bits and also standards associated with drill sizes. We also learned different representation of Drill Size Chart and also all the important Drill Bit Size Chart.



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