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Tap Drill Chart | Metric, Inch, National Coarse, National Fine

While Drilling is the process of making holes in a material (wood, masonry, metal, etc.), Tapping is the process of creating threads inside those holes for inserting screws. In the previous guide, we saw Drill Sizes Chart for various standards. But if you want to properly insert screws in the holes, then you need a Tap Drill Chart. So, in this guide, let us take a quick look at different Tap Drill Charts based on different standards.

A Brief Note on Drill and Tap

The combination of Drills and Drill Bits allow you to make holes in wood, bricks, concrete, metal and other materials. If you want to insert screws or bolts into these holes, then you need proper threaded walls on the holes. This is where a ‘Tap’ comes into play.

It is a tool that can create screw threads in holes created by drills. The process of creating threads in drill holes is known as Tapping.

Tap Drill Chart

Just like other sizes, even Tap Drill Sizes are available in both metric and imperial. We will take a look at different tap drill charts based on the drill sizes.

Number Size Tap Drill Chart

Tap Size Drill Size Decimal Value (in)
0 – 80 3/64” 0.0469
1 – 64 #53 0.0595
1 – 72 #53 0.0595
2 – 56 #50 0.07
2 – 64 #50 0.07
3 – 48 #47 0.0785
3 – 56 #46 0.081
4 – 40 #43 0.089
4 – 48 #42 0.0935
5 – 40 #38 0.1015
5 – 44 #37 0.104
6 – 32 #36 0.1065
6 – 40 #33 0.113
8 – 32 #29 0.136
8 – 36 #29 0.136
10 – 24 #26 0.147
10 – 32 #21 0.159
12 – 24 #16 0.177
12 – 28 #15 0.18
14 – 20 #10 0.1935
14 – 24 #7 0.201

Metric Tap Drill Chart

Tap Size Drill Size (mm) Decimal Value (in)
M1.6 × 0.35 1.25 0.0492
M1.8 × 0.35 1.45 0.0571
M2 × 0.4 1.6 0.063
M2.2 × 0.45 1.75 0.0689
M2.5 × 0.45 2.05 0.0807
M3 × 0.5 2.5 0.0984
M3.5 × 0.6 2.9 0.1142
M4 × 0.7 3.3 0.1299
M4.5 × 0.75 3.7 0.1476
M5 × 0.8 4.2 0.1654
M6 × 1.0 5 0.1969
M7 × 1.0 6 0.2362
M8 × 1.25 6.7 0.2638
M8 × 1.0 7 0.2756
M10 × 1.5 8.5 0.3346
M10 × 1.25 8.7 0.3425
M12 × 1.75 10.2 0.4016
M12 × 1.25 10.8 0.4252
M14 × 2.0 12 0.4224
M16 × 2.0 14 0.5512
M16 × 1.5 14.5 0.5906
M18 × 2.5 15.5 0.6102
M18 × 1.5 16.5 0.6496
M20 × 2.5 17.5 0.689
M20 × 1.5 18.5 0.7283
M22 × 2.5 19.5 0.7677
M22 × 1.5 20.5 0.8071
M24 × 3.0 21 0.8268
M24 × 2.0 22 0.8661
M27 × 3.0 24 0.9449
M27 × 2.0 25 0.9843
M30 × 3.5 26.5 1.0433
M30 × 2.0 28 1.1024
M33 × 3.5 29.5 1.1614
M33 × 2.0 31 1.2205
M36 × 4.0 32 1.2598
M36 × 3.0 33 1.2992
M39 × 4.0 35 1.378
M39 × 3.0 36 1.4173

Fractional Inch Tap Drill Sizes

Tap Size (in) Drill Size Decimal Value (in)
1/4 – 20 #7 0.201
1/4 – 28 #3 0.213
5/16 – 18 F 0.257
5/16 – 24 I 0.272
3/8 – 16 5/16 0.3125
3/8 – 24 Q 0.332
7/16 – 14 U 0.368
7/16 – 20 25/64 0.3906
1/2 – 13 27/67 0.4219
1/2 – 20 29/64 0.4531
9/16 – 12 31/64 0.4844
9/16 – 18 33/64 0.5156
5/8 – 11 14/32 0.5312
5/8 – 18 37/64 0.5781
3/4 – 10 21/32 0.6562
3/4 – 16 11/16 0.6875
7/8 – 9 49/64 0.7656
7/8 – 14 13/16 0.8125
1 – 8 7/8 0.875
1 – 12 59/64 0.9219
1-1/8 – 7 63/64 0.9844
1-1/8 – 12 1-3/64 1.0469
1-1/4 – 7 1-7/64 1.1094
1-1/4 – 12 1-11/64 1.1719
1-3/8 – 6 1-7/32 1.2188
1-3/8 – 12 1-19/64 1.2969
1-1/2 – 6 1-11/32 1.3438
1-1/2 – 12 1-27/64 1.4219

Unified National Coarse Tap Drill Sizes

Tap Size Drill Size Decimal Value (in)
1 – 64 #53 0.0595
2 – 56 #50 0.07
3 – 48 #47 0.0785
4 – 40 #43 0.089
5 – 40 #38 0.1015
6 – 32 #36 0.1065
8 – 32 #29 0.136
10 – 24 #26 0.147
12 – 24 #16 0.177
1/4 – 20 #7 0.201
5/16 – 18 F 0.257
3/8 – 16 5/16 0.3125
7/16 – 14 U 0.368
1/2 – 13 27/64 0.368
9/16 – 12 31/64 0.4844
5/8 – 11 17/32 0.5312
3/4 – 10 21/32 0.6562
7/8 – 9 49/64 0.7656
1 – 8 7/8 0.875
1-1/8 – 7 63/34 0.9844
1-1/4 – 7 1-7/64 1.1094
1-3/8 – 6 1-1/64 1.2188
1-1/2 – 6 1-11/54 1.3438

Unified National Fine Tap Drill Sizes

Tap Size Drill Size Decimal Value (in)
0 – 80 3/64” 0.0469
1 – 72 #53 0.0595
2 – 64 #50 0.07
3 – 56 #46 0.081
4 – 48 #42 0.0935
5 – 44 #37 0.104
6 – 40 #33 0.113
8 – 36 #29 0.136
10 – 32 #21 0.159
12 – 28 #15 0.18
1/4 – 28 #3 0.213
5/16 – 24 I 0.272
3/8 – 24 Q 0.332
7/16 – 20 25/64 0.3906
1/2 – 20 29/64 0.4531
9/16 – 18 33/64 0.5156
5/8 – 18 37/64 0.5781
3/4 – 16 11/16 0.6875
7/8 – 14 13/16 0.8125
1 – 12 59/64 0.9219
1-1/8 – 12 1-3/64 1.0469
1-1/4 – 12 1-11/64 1.1719
1-3/8 – 12 1-19/64 1.2969
1-1/2 – 12 1-27/64 1.4219

National Standard Tap Drill Sizes

Tap Size Drill Size
5/32 – 32 1/8
5/32 – 36 #30
3/16 – 24 #26
3/16 – 32 #22
7/32 – 24 #16
7/32 – 32 #12
1/4 – 32 7/32
1/4 – 40 #1
5/16 – 32 9/32
11/16 – 16 5/8
1 – 14 15/16

National Pipe Thread Tap Drill Sizes

Tap Size Drill Size
1/8 – 27 Q
1/4 – 18 7/16
3/8 – 18 9/16
1/2 – 14 23/32
3/4 – 14 59/64
1 – 11-1/2 1-5/32
1-1/4 – 11-1/2 1-1/2
1-1/2 – 11-1/2 1-47/64
2 – 11-1/2 2-7/32

Conclusion

If you want to create screw threads in holes, hen you have to use a Tap (a tool that forms threads). And the process of creating these threads is known as Tapping. Since tapping and Drilling are closely related to each other, if you want to tap a hole, then the diameter of the hole is very important. This is where the Tap Drill Chart can be handy. You can use these charts as a reference to properly drill holes and tap them.

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