Drill bit Length Chart

Drill bit Length Chart

The table shows the sizes of straight shank drills.

In the United States, three different systems for designating twist drill sizes are used:

  • letters (Morse gauge)
  • fractional inches
  • millimeters
  • numbers, with higher numbers representing smaller drills.

The lengths in the table are “jobber’s lengths”. Very long twist drills, (“aircraft drills” or “electrician’s drill”) are available in 6, 12, and even 24-inch lengths.

Size Long Length Regular Length Short Length
Size Flute Length Flute Length Overall Length Overall Length Dec. Flute Length Overall Length
1/64 5/16 3/16 3/4 1-1/2 0.0156
1/32 3/4 1/2 1-3/8 2 0.0312
3/64 1-1/8 3/4 1-3/4 2-1/4 0.0469 1/2 1-3/8
1/16 1-3/4 7/8 1-7/8 3 0.0625 5/8 1-5/8
5/64 2 1 2 3-3/4 0.0781 11/16 1-11/16
3/32 2-1/4 1-1/4 2-1/4 4-1/4 0.0937 3/4 1-3/4
7/64 2-1/2 1-1/2 2-5/8 4-5/8 0.1094 13/16 1-13/16
1/8 2-3/4 1-5/8 2-3/4 5-1/8 0.1250 7/8 1-7/8
9/64 3 1-3/4 2-7/8 5-3/8 0.1406 15/16 1-15/16
5/32 3 2 3-1/8 5-3/8 0.1562 1 2-1/16
11/64 3-3/8 2-1/8 3-1/4 5-3/4 0.1719 1-1/16 2-1/8
3/16 3-3/8 2-5/16 3-1/2 5-3/4 0.1875 1-1/8 2-3/16
13/64 3-5/8 2-7/16 3-5/8 6 0.2031 1-3/16 2-1/4
7/32 3-5/8 2-1/2 3-3/4 6 0.2188 1-1/4 2-3/8
15/64 3-3/4 2-5/8 3-7/8 6-1/8 0.2344 1-5/16 2-7/16
1/4 3-3/4 2-3/4 4 6-1/8 0.2500 1-3/8 2-1/2
17/64 3-7/8 2-7/8 4-1/8 6-1/4 0.2656 1-7/16 2-5/8
9/32 3-7/8 2-15/16 4-1/4 6-1/4 0.2812 1-1/2 2-11/16
19/64 4 3-1/16 4-3/8 6-3/8 0.2969 1-9/16 2-3/4
5/16 4 3-3/16 4-1/2 6-3/8 0.3125 1-5/8 2-13/16
21/64 4-1/8 3-5/16 4-5/8 6-1/2 0.3281 1-11/16 2-15/16
11/32 4-1/8 3-7/16 4-3/4 6-1/2 0.3438 1-11/16 3
23/64 4-1/4 3-1/2 4-7/8 6-3/4 0.3594 1-3/4 3-1/16
3/8 4-1/4 3-5/8 5 6-3/4 0.3750 1-13/16 3-1/8
25/64 4-3/8 3-3/4 5-1/8 7 0.3906 1-7/8 3-1/4
13/32 4-3/8 3-7/8 5-1/4 7 0.4062 1-15/16 3-5/16
27/64 4-5/8 3-15/16 5-3/8 7-1/4 0.4219 2 3-3/8
7/16 4-5/8 4-1/16 5-1/2 7-1/4 0.4375 2-1/16 3-7/16
29/64 4-3/4 4-3/16 5-5/8 7-1/2 0.4531 2-1/8 3-9/16
15/32 4-3/4 4-5/16 5-3/4 7-1/2 0.4688 2-1/8 3-5/8
31/64 4-3/4 4-3/8 5-7/8 7-3/4 0.4844 2-3/16 3-11/16
1/2 4-3/4 4-1/2 6 7-3/4 0.5000 2-1/4 3-3/4
33/64 4-3/4 4-13/16 6-5/8 8 0.5156 2-3/8 3-7/8
17/32 4-3/4 4-13/16 6-5/8 8 0.5312 2-3/8 3-7/8
35/64 4-7/8 4-1316 6-5/8 8-1/4 0.5469 2-1/2 4
9/16 4-7/8 4-13/16 6-5/8 8-1/4 0.5625 2-1/2 4
37/64 4-7/8 4-13/16 6-5/8 8-3/4 0.5781 2-5/8 4-1/8
19/32 4-7/8 5-3/16 7-1/8 8-3/4 0.5938 2-5/8 4-1/8
39/64 4-7/8 5-3/16 7-1/8 8-3/4 0.6094 2-3/4 4-1/4
5/8 4-7/8 5-3/16 7-1/8 8-3/4 0.6250 2-3/4 4-1/4
41/64 5-1/8 5-3/16 7-1/8 9 0.6406 2-7/8 4-1/2
21/32 5-1/8 5-3/16 7-1/8 9 0.6562 2-7/8 4-1/2
43/64 5-3/8 5-5/8 7-5/8 9-1/4 0.6719 2-7/8 4-5/8
11/16 5-3/8 5-5/8 7-5/8 9-1/4 0.6875 2-7/8 4-5/8
45/64 5-5/8 9-1/2 0.7031 3 4-3/4
23/32 5-5/8 9-1/2 0.7188 3 4-3/4
47/64 5-7/8 9-3/4 0.7344 3-1/8 5
3/4 5-7/8 9-3/4 0.7500 3-1/8 5
49/64 6 9-7/8 0.7656 3-1/4 5-1/8
25/32 6 9-7/8 0.7812 3-1/4 5-1/8
51/64 6-1/8 10 0.7969 3-3/8 5-1/4
13/16 6-1/8 10 0.8125 3-3/8 5-1/4
53/64 6-1/8 10 0.8281 3-1/2 5-3/8
27/32 6-1/8 10 0.8438 3-1/2 5-3/8
55/64 6-1/8 10 0.8594 3-1/2 5-1/2
7/8 6-1/8 10 0.8750 3-1/2 5-1/2
57/64 6-1/8 10 0.8906 3-5/8 5-5/8
29/32 6-1/8 10 0.9062 3-5/8 5-5/8
59/64 6-1/8 10-3/4 0.9219 3-3/4 5-3/4
15/16 6-1/8 10-3/4 0.9375 3-3/4 5-3/4
61/64 6-3/8 11 0.9531 3-7/8 5-7/8
31/32 6-3/8 11 0.9688 3-7/8 5-7/8
63/64 6-3/8 11 0.9844 4 6
1 6-3/8 11 10.000 4 6
1-1/8 7-1/8 11-3/4 10.125 4 6-3/8

Price: $11.45

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