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.

SizeLong LengthRegular LengthShort Length
SizeFlute LengthFlute LengthOverall LengthOverall LengthDec.Flute LengthOverall Length
1/645/163/163/41-1/20.0156
1/323/41/21-3/820.0312
3/641-1/83/41-3/42-1/40.04691/21-3/8
1/161-3/47/81-7/830.06255/81-5/8
5/642123-3/40.078111/161-11/16
3/322-1/41-1/42-1/44-1/40.09373/41-3/4
7/642-1/21-1/22-5/84-5/80.109413/161-13/16
1/82-3/41-5/82-3/45-1/80.12507/81-7/8
9/6431-3/42-7/85-3/80.140615/161-15/16
5/32323-1/85-3/80.156212-1/16
11/643-3/82-1/83-1/45-3/40.17191-1/162-1/8
3/163-3/82-5/163-1/25-3/40.18751-1/82-3/16
13/643-5/82-7/163-5/860.20311-3/162-1/4
7/323-5/82-1/23-3/460.21881-1/42-3/8
15/643-3/42-5/83-7/86-1/80.23441-5/162-7/16
1/43-3/42-3/446-1/80.25001-3/82-1/2
17/643-7/82-7/84-1/86-1/40.26561-7/162-5/8
9/323-7/82-15/164-1/46-1/40.28121-1/22-11/16
19/6443-1/164-3/86-3/80.29691-9/162-3/4
5/1643-3/164-1/26-3/80.31251-5/82-13/16
21/644-1/83-5/164-5/86-1/20.32811-11/162-15/16
11/324-1/83-7/164-3/46-1/20.34381-11/163
23/644-1/43-1/24-7/86-3/40.35941-3/43-1/16
3/84-1/43-5/856-3/40.37501-13/163-1/8
25/644-3/83-3/45-1/870.39061-7/83-1/4
13/324-3/83-7/85-1/470.40621-15/163-5/16
27/644-5/83-15/165-3/87-1/40.421923-3/8
7/164-5/84-1/165-1/27-1/40.43752-1/163-7/16
29/644-3/44-3/165-5/87-1/20.45312-1/83-9/16
15/324-3/44-5/165-3/47-1/20.46882-1/83-5/8
31/644-3/44-3/85-7/87-3/40.48442-3/163-11/16
1/24-3/44-1/267-3/40.50002-1/43-3/4
33/644-3/44-13/166-5/880.51562-3/83-7/8
17/324-3/44-13/166-5/880.53122-3/83-7/8
35/644-7/84-13166-5/88-1/40.54692-1/24
9/164-7/84-13/166-5/88-1/40.56252-1/24
37/644-7/84-13/166-5/88-3/40.57812-5/84-1/8
19/324-7/85-3/167-1/88-3/40.59382-5/84-1/8
39/644-7/85-3/167-1/88-3/40.60942-3/44-1/4
5/84-7/85-3/167-1/88-3/40.62502-3/44-1/4
41/645-1/85-3/167-1/890.64062-7/84-1/2
21/325-1/85-3/167-1/890.65622-7/84-1/2
43/645-3/85-5/87-5/89-1/40.67192-7/84-5/8
11/165-3/85-5/87-5/89-1/40.68752-7/84-5/8
45/645-5/89-1/20.703134-3/4
23/325-5/89-1/20.718834-3/4
47/645-7/89-3/40.73443-1/85
3/45-7/89-3/40.75003-1/85
49/6469-7/80.76563-1/45-1/8
25/3269-7/80.78123-1/45-1/8
51/646-1/8100.79693-3/85-1/4
13/166-1/8100.81253-3/85-1/4
53/646-1/8100.82813-1/25-3/8
27/326-1/8100.84383-1/25-3/8
55/646-1/8100.85943-1/25-1/2
7/86-1/8100.87503-1/25-1/2
57/646-1/8100.89063-5/85-5/8
29/326-1/8100.90623-5/85-5/8
59/646-1/810-3/40.92193-3/45-3/4
15/166-1/810-3/40.93753-3/45-3/4
61/646-3/8110.95313-7/85-7/8
31/326-3/8110.96883-7/85-7/8
63/646-3/8110.984446
16-3/81110.00046
1-1/87-1/811-3/410.12546-3/8

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