Tap size Drilling chart
The tap size chart provides a list of standard size taps, specifying the diameter and thread spacing, for
fractional, metric, and screw sizes. The decimal equivalents of the diameters are shown in both English
and Metric units. Fractional sizes are listed in inches, while metric sizes are listed in millimeters following
the letter “M”. A screw size number corresponds to a diameter which is larger for a higher screw size.
The thread spacing, which may be coarse or fine, is listed after the diameter. In the fractional and screw
size systems, the thread count is used, measured in threads per inch. The metric system uses the thread
pitch, which is the distance between threads, measured in millimeters. For each thread count, the
equivalent thread pitch is provided and for metric taps, the approximate thread count is shown based
on the pitch. Lastly, the recommended tap drill size is provided for each standard tap size. This size drill
bit should be used for drilling the initial hole that will then be tapped.
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
#0000-
0.0210 0.5334 160 0.159 1/64 in
160
#000-120 0.0340 0.8636 120 0.212 #71
M1x0.2 0.0394 1.0000 ~127 0.200 0.8 mm
M1x0.25 0.0394 1.0000 ~102 0.250 0.75 mm
M1.1×0.2
0.0433 1.1000 ~102 0.250 0.85 mm
5
M1.1×0.2 0.0433 1.1000 ~127 0.200 0.9 mm
#00-90 0.0470 1.1938 90 0.282 #65
M1.2×0.2 0.0472 1.2000 ~127 0.200 1 mm
M1.2×0.2
0.0472 1.2000 ~102 0.250 0.95 mm
5
M1.4×0.2 0.0551 1.4000 ~127 0.200 1.2 mm
M1.4×0.3 0.0551 1.4000 ~85 0.300 1.1 mm
#0-80 0.0600 1.5240 80 0.318 3/64 in
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
M1.6×0.2 0.0630 1.6000 ~127 0.200 1.4 mm
M1.6×0.3
0.0630 1.6000 ~73 0.350 1.25 mm
5
M1.8×0.2 0.0709 1.8000 ~127 0.200 1.6 mm
M1.8×0.3
0.0709 1.8000 ~73 0.350 1.45 mm
5
#1-64 0.0730 1.8542 64 0.397 #52
#1-72 0.0730 1.8542 72 0.353 #53
M2x0.25 0.0787 2.0000 ~102 0.250 1.75 mm
M2x0.4 0.0787 2.0000 ~64 0.400 1.6 mm
#2-56 0.0860 2.1844 56 0.454 #50
#2-64 0.0860 2.1844 64 0.397 #50
M2.2×0.2
0.0866 2.2000 ~102 0.250 1.95 mm
5
M2.2×0.4
0.0866 2.2000 ~57 0.450 1.75 mm
5
M2.5×0.3
0.0984 2.5000 ~73 0.350 2.1 mm
5
M2.5×0.4
0.0984 2.5000 ~57 0.450 2.05 mm
5
#3-48 0.0990 2.5146 48 0.529 #47
#3-56 0.0990 2.5146 56 0.454 #45
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
#4-40 0.1120 2.8448 40 0.635 #43
#4-48 0.1120 2.8448 48 0.529 #42
M3x0.35 0.1181 3.0000 ~73 0.350 2.6 mm
M3x0.5 0.1181 3.0000 ~51 0.500 2.5 mm
#5-40 0.1250 3.1750 40 0.635 #39
#5-44 0.1250 3.1750 44 0.577 #37
M3.5×0.3
0.1378 3.5000 ~73 0.350 3.1 mm
5
M3.5×0.6 0.1378 3.5000 ~43 0.600 2.9 mm
#6-32 0.1380 3.5052 32 0.794 #36
#6-40 0.1380 3.5052 40 0.635 #33
M4x0.35 0.1575 4.0000 ~73 0.350 3.6 mm
M4x0.5 0.1575 4.0000 ~51 0.500 3.5 mm
M4x0.7 0.1575 4.0000 ~37 0.700 3.3 mm
#8-32 0.1640 4.1656 32 0.794 #29
#8-36 0.1640 4.1656 36 0.706 #29
M4.5×0.5 0.1772 4.5000 ~51 0.500 4 mm
M4.5×0.7
0.1772 4.5000 ~34 0.750 3.8 mm
5
#10-32 0.1900 4.8260 32 0.794 #21
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
#10-24 0.1900 4.8260 24 1.058 #25
M5x0.5 0.1969 5.0000 ~51 0.500 4.5 mm
M5x0.8 0.1969 5.0000 ~32 0.800 4.2 mm
#12-24 0.2160 5.4864 24 1.058 #17
#12-28 0.2160 5.4864 28 0.907 #15
M5.5×0.5 0.2165 5.5000 ~51 0.500 5 mm
M6x0.5 0.2362 6.0000 ~51 0.500 5.5 mm
M6x0.75 0.2362 6.0000 ~34 0.750 5.2 mm
M6x1 0.2362 6.0000 ~26 1.000 5 mm
1/4-20 0.2500 6.3500 20 1.270 #7
1/4-28 0.2500 6.3500 28 0.907 #3
M7x0.75 0.2756 7.0000 ~34 0.750 6.2 mm
M7x1 0.2756 7.0000 ~26 1.000 6 mm
5/16-18 0.3125 7.9375 18 1.411 F
5/16-24 0.3125 7.9375 24 1.058 I
M8x0.5 0.3150 8.0000 ~51 0.500 7.5 mm
M8x0.75 0.3150 8.0000 ~34 0.750 7.2 mm
M8x1 0.3150 8.0000 ~26 1.000 7 mm
M8x1.25 0.3150 8.0000 ~21 1.250 6.8 mm
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
M9x0.75 0.3543 9.0000 ~34 0.750 8.2 mm
M9x1 0.3543 9.0000 ~26 1.000 8 mm
M9x1.25 0.3543 9.0000 ~21 1.250 7.8 mm
3/8-24 0.3750 9.5250 24 1.058 Q
3/8-16 0.3750 9.5250 16 1.588 5/16 in
M10x0.7
0.3937 10.0000 ~34 0.750 9.2 mm
5
M10x1.5 0.3937 10.0000 ~17 1.500 8.5 mm
M10x1.2
0.3937 10.0000 ~21 1.250 8.8 mm
5
M10x1 0.3937 10.0000 ~26 1.000 9 mm
M11x0.7
0.4331 11.0000 ~34 0.750 10.2 mm
5
M11x1 0.4331 11.0000 ~26 1.000 10 mm
M11x1.5 0.4331 11.0000 ~17 1.500 9.5 mm
7/16-14 0.4375 11.1125 14 1.814 U
7/16-20 0.4375 11.1125 20 1.270 25/64 in
M12x1.5 0.4724 12.0000 ~17 1.500 10.5 mm
M12x1.7
0.4724 12.0000 ~15 1.750 10.2 mm
5
M12x0.7
0.4724 12.0000 ~34 0.750 11.25 mm
5
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
M12x1 0.4724 12.0000 ~26 1.000 11 mm
M12x1.2
0.4724 12.0000 ~21 1.250 10.8 mm
5
1/2-20 0.5000 12.7000 20 1.270 29/64 in
1/2-13 0.5000 12.7000 13 1.954 27/64 in
M14x1.5 0.5512 14.0000 ~17 1.500 12.5 mm
M14x1.2
0.5512 14.0000 ~21 1.250 12.8 mm
5
M14x1 0.5512 14.0000 ~26 1.000 13 mm
M14x2 0.5512 14.0000 ~13 2.000 12 mm
9/16-18 0.5625 14.2875 18 1.411 33/64 in
9/16-12 0.5625 14.2875 12 2.117 31/64 in
M15x1 0.5906 15.0000 ~26 1.000 14 mm
M15x1.5 0.5906 15.0000 ~17 1.500 13.5 mm
5/8-18 0.6250 15.8750 18 1.411 37/64 in
5/8-11 0.6250 15.8750 11 2.309 17/32 in
M16x2 0.6299 16.0000 ~13 2.000 14 mm
M16x1.5 0.6299 16.0000 ~17 1.500 14.5 mm
M16x1 0.6299 16.0000 ~26 1.000 15 mm
M17x1 0.6693 17.0000 ~26 1.000 16 mm
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
M17x1.5 0.6693 17.0000 ~17 1.500 15.5 mm
M18x2.5 0.7087 18.0000 ~11 2.500 15.5 mm
M18x1 0.7087 18.0000 ~26 1.000 17 mm
M18x1.5 0.7087 18.0000 ~17 1.500 16.5 mm
M18x2 0.7087 18.0000 ~13 2.000 16 mm
3/4-16 0.7500 19.0500 16 1.588 11/16 in
3/4-10 0.7500 19.0500 10 2.540 21/32 in
M20x2 0.7874 20.0000 ~13 2.000 18 mm
M20x1.5 0.7874 20.0000 ~17 1.500 18.5 mm
M20x1 0.7874 20.0000 ~26 1.000 19 mm
M20x2.5 0.7874 20.0000 ~11 2.500 17.5 mm
M22x2 0.8661 22.0000 ~13 2.000 20 mm
M22x1.5 0.8661 22.0000 ~17 1.500 20.5 mm
M22x1 0.8661 22.0000 ~26 1.000 21 mm
M22x2.5 0.8661 22.0000 ~11 2.500 19.5 mm
7/8-9 0.8750 22.2250 9 2.822 49/64 in
7/8-14 0.8750 22.2250 14 1.814 13/16 in
M24x3 0.9449 24.0000 ~9 3.000 21 mm
M24x1 0.9449 24.0000 ~26 1.000 23 mm
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
M24x1.5 0.9449 24.0000 ~17 1.500 22.5 mm
M24x2 0.9449 24.0000 ~13 2.000 22 mm
M25x2 0.9843 25.0000 ~13 2.000 23 mm
M25x1 0.9843 25.0000 ~26 1.000 24 mm
M25x1.5 0.9843 25.0000 ~17 1.500 23.5 mm
1-14 1.0000 25.4000 14 1.814 15/16 in
1-8 1.0000 25.4000 8 3.175 7/8 in
M26x1.5 1.0236 26.0000 ~17 1.500 24.5 mm
M27x1.5 1.0630 27.0000 ~17 1.500 25.5 mm
M27x3 1.0630 27.0000 ~9 3.000 24 mm
M27x1 1.0630 27.0000 ~26 1.000 26 mm
M27x2 1.0630 27.0000 ~13 2.000 25 mm
M28x2 1.1024 28.0000 ~13 2.000 26 mm
M28x1 1.1024 28.0000 ~26 1.000 27 mm
M28x1.5 1.1024 28.0000 ~17 1.500 26.5 mm
1 1/8-12 1.1250 28.5750 12 2.117 1 3/64 in
1 1/8-7 1.1250 28.5750 7 3.629 63/64 in
M30x1.5 1.1811 30.0000 ~17 1.500 28.5 mm
M30x3.5 1.1811 30.0000 ~8 3.500 26.5 mm
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
M30x2 1.1811 30.0000 ~13 2.000 28 mm
1 1/4-12 1.2500 31.7500 12 2.117 1 11/64 in
1 1/4-7 1.2500 31.7500 7 3.629 1 7/64 in
M33x2 1.2992 33.0000 ~13 2.000 31 mm
M33x3.5 1.2992 33.0000 ~8 3.500 29.5 mm
M36x3 1.4173 36.0000 ~9 3.000 33 mm
M36x4 1.4173 36.0000 ~7 4.000 32 mm
1 1/2 -12 1.5000 38.1000 12 2.117 1 27/64 in
1 1/2-6 1.5000 38.1000 6 4.233 1 11/32 in
M39x4 1.5354 39.0000 ~7 4.000 35 mm
M39x3 1.5354 39.0000 ~9 3.000 36 mm
M42x4.5 1.6535 42.0000 ~6 4.500 37.5 mm
1 3/4-12 1.7500 44.4500 12 2.117 1 43/64 in
1 3/4-5 1.7500 44.4500 5 5.080 1 35/64 in
M45x4.5 1.7717 45.0000 ~6 4.500 40.5 mm
M48x5 1.8898 48.0000 ~6 5.000 43 mm
2-12 2.0000 50.8000 12 2.117 1 59/64 in
2-4 1/2 2.0000 50.8000 4.5 5.644 1 25/32 in
M52x5 2.0472 52.0000 ~6 5.000 47 mm
Thread Thread
Diameter Diameter Tap drill
Tap size count pitch
(in) (mm) size
(TPI) (mm)
M56x5.5 2.2047 56.0000 ~5 5.500 50.5 mm
M60x5.5 2.3622 60.0000 ~5 5.500 54.5 mm
M64x6 2.5197 64.0000 ~5 6.000 58 mm
M68x6 2.6772 68.0000 ~5 6.000 62 mm
