Tap and drill chart

Tap and drill reference pairing each screw or bolt size with the correct drill bit, closest fractional size and decimal equivalent.

Tap and drill chart
To tap this size screw or bolt Use this drill bit Closest fractional Decimal inches
0–80 NF 3/64″ 3/64″ .0469
0-80 NF 3/64″ 3/64″ .0469
1-64 NC #53 – .0595
1-72 NF #53 1/16″ .0595
2-56 NC #50 – .0700
2-64 NF #50 – .0700
3-48 NC #47 5/64″ .0785
3-56 NF #45 – .0820
4-36 NS #44 – .0860
4-40 NC #43 3/32″ .0890
4-48 NF #42 3/32″ .0935
3mm- .060mm 2.5mm – .0984
1/8-40 NS #38 – .1015
5-40 NC #38 – .1015
5-44 NF #37 – .1040
6-32 NC #35 7/64″ .1100
6-36 NS #34 – .1110
6-40 NF #33 – .1130
6-48 NS #31 – .1200
4mm-0.70mm 3.4mm – .1338
4mm-.075mm 3.4mm – .1338
8-32 NC #29 – .1360
8-36 NF #29 9/64″ .1360
8-40 NS #28 – .1405
3/16-24 NS #26 – .1470
10-24 NC #25 5/32″ .1495
3/16-32 NS #22 – .1570
10-32 NF #21 5/32″ .1590
5mm-.090mm 4.2mm – .1653
5mm-.080mm 4.3mm – .1693
12-24 NC #16 11/64″ .1770
12-28 NF #14 3/16″ .1820
12-32 NEF #13 – .1850
14-20 NS #10 – .1935
1//4-20 NC #7 13/64″ .2010
14-24 NS #7 – .2010
6mm-1.00mm 5.2mm – .2047
1/4-24 NS #4 – .2090
1/4-28 NF #3 7/32″ .2130
1/4-32 NEF 7/32″ 7/32″ .2188
1/4-40 NS #1 – .2280
7mm-1.00mm 6.1mm 15/64″ .2401
5/16-18 NC Ltr.F 17/64″ .2570
8mm-1.25mm 6.9mm 17/64″ .2716
5/16-24 NF Ltr.I – .2720
8mm-1.00mm 7.1mm – .2795
5/16-32 NEF 9/32″ 9/32″ .2812
9mm-1.25mm 7.9mm – .3110
3/8-16 NC 5/16″ 5/16″ .3125
9mm-1.00mm 8.1mm – .3189
9mm-0.75mm 8.3mm – .3268
3/8-24 NF Ltr.Q 21/64″ .3320
10mm- 1.50mm 8.7mm – .3425
10mm- 1.25mm 8.9mm 11/32″ .3503
10mm- 1.00mm* 9.1mm – .3583
7/16- 14 NC Ltr.U 23/64″ .3680
11mm 1.50mm 9.7mm – .3818
7/16-20 NF 25/64″ 25/64″ .3906
12mm- 1.75mm 10.5mm – .4133
12mm- 1.50mm 10.7mm 27/64″ .4212
1/2-13 NC 27/64″ 27/64″ .4219
12mm- 1.25mm* 10.9mm 27/64″ .4291
1/2-20 NF 29/64″ 29/64″ .4531
1/2-24 NS 29/64″ 29/64″ .4531
14mm-2.00mm 12.2mm – .4803
9/16-12 NC 31/64″ 31/64″ .4844
14mm- 1.50mm 12.7mm – .4999
14mm-1.25mm* 12.8mm – .5039
9/16-18 NF 33/64″ 33/64″ .5156
5/8-11 NC 17/32″ 17/32″ .5312
16mm-2.00mm 14.2mm 35/64″ .5590
5/8-18 NF 37/64″ 37/64″ .5781
16mm- 1.50mm 14.7mm – .5787
11/16-11 NS 19/32″ 19/32″ .5938
18mm-2.50mm 15.8mm 39/64″ .5220
11/16-16 NS 5/8″ 5/8″ .6250
3/4-10 NC 21/32″ 21/32″ .6562
18mm-1.50mm* 16.8mm – .6614
3/4-16 NF 11/16″ 11/16″ .6875
20mm-2.50mm 17.8mm 11/16″ .7008
7/8-9 NC 49/64″ 49/64″ .7656
7/8-14 NF 13/16″ 13/16″ .8125
22mm-1.50mm 20.9mm – .8228
7/8-18 NS* 53/64″ 53/64″ .8281
24mm-3.00mm 21.4mm 53/64″ .8425
1.8 NC 7/8″ 7/8″ .8750
24mm-2.00mm 22.3mm – .8779
1.12 NF 59/64″ 59/64″ .9219
1-14 NS 15/16″ 15/16″ .9375
1 1/8-7 NC 63/64″ 63/64″ .9844
1 1/8-12 NF 1 3/64″ 1 3/64″ 1.0469
1 1/4-7 NC 1 7/64″ 1 7/64″ 1.1094
1 1/4-12 NF 1 11/64″ 1 11/64″ 1.1719
1 3/8-6 NC 1 7/32″ 1 7/32″ 1.2188
1 3/8-12 NF 1 19/64″ 1 19/64″ 1.2969
1 1/2-6 NC 1 11/32″ 1 11/32″ 1.3438
1 1/2″-12 NF 1 27/64″ 1 27/64″ 1.4219
*These Sizes Are Spark Plug Taps