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Tap Drill Size Chart

Find the right tap drill size, clearance drill size, and decimal equivalent for standard and metric threads.

Standard (US) tap drill and clearance drill sizes
Standard (US) Sizes				Tap Drill				Clearance Drill
Screw Size	Major Diameter	Threads Per Inch	Minor Diameter	Tap Drill				Clearance Drill
				75% Thread for Aluminum, Brass, & Plastics		50% Thread for Steel, Stainless, & Iron		Close Fit		Free Fit
				Drill Size	Decimal Equiv.	Drill Size	Decimal Equiv.	Drill Size	Decimal Equiv.	Drill Size	Decimal Equiv.
0	.0600	80	.0447	3/64	.0469	55	.0520	52	.0635	50	.0700
1	.0730	64	.0538	53	.0595	1/16	.0625	48	.0760	46	.0810
1	.0730	72	.0560	53	.0595	52	.0635	48	.0760	46	.0810
2	.0860	56	.0641	50	.0700	49	.0730	43	.0890	41	.0960
2	.0860	64	.0668	50	.0700	48	.0760	43	.0890	41	.0960
3	.0990	48	.0734	47	.0785	44	.0860	37	.1040	35	.1100
3	.0990	56	.0771	45	.0820	43	.0890	37	.1040	35	.1100
4	.1120	40	.0813	43	.0890	41	.0960	32	.1160	30	.1285
4	.1120	48	.0864	42	.0935	40	.0980	32	.1160	30	.1285
5	.125	40	.0943	38	.1015	7/64	.1094	30	.1285	29	.1360
5	.125	44	.0971	37	.1040	35	.1100	30	.1285	29	.1360
6	.138	32	.0997	36	.1065	32	.1160	27	.1440	25	.1495
6	.138	40	.1073	33	.1130	31	.1200	27	.1440	25	.1495
8	.1640	32	.1257	29	.1360	27	.1440	18	.1695	16	.1770
8	.1640	36	.1299	29	.1360	26	.1470	18	.1695	16	.1770
10	.1900	24	.1389	25	.1495	20	.1610	9	.1960	7	.2010
10	.1900	32	.1517	21	.1590	18	.1695	9	.1960	7	.2010
12	.2160	24	.1649	16	.1770	12	.1890	2	.2210	1	.2280
		28	.1722	14	.1820	10	.1935
		32	.1777	13	.1850	9	.1960
1/4	.2500	20	.1887	7	.2010	7/32	.2188	F	.2570	H	.2660
		28	.2062	3	.2130	1	.2280
		32	.2117	7/32	.2188	1	.2280
5/16	.3125	18	.2443	F	.2570	J	.2770	P	.3230	Q	.3320
		24	.2614	I	.2720	9/32	.2812
		32	.2742	9/32	.2812	L	.2900
3/8	.3750	16	.2983	5/16	.3125	Q	.3320	W	.3860	X	.3970
		24	.3239	Q	.3320	S	.3480
		32	.3367	11/32	.3438	T	.3580
7/16	.4375	14	.3499	U	.3680	25/64	.3906	29/64	.4531	15/32	.4687
		20	.3762	25/64	.3906	13/32	.4062
		28	.3937	Y	.4040	Z	.4130
1/2	.5000	13	.4056	27/64	.4219	29/64	.4531	33/64	.5156	17/32	.5312
		20	.4387	29/64	.4531	15/32	.4688
		28	.4562	15/32	.4688	15/32	.4688
9/16	.5625	12	.4603	31/64	.4844	33/64	.5156	37/64	.5781	19/32	.5938
		18	.4943	33/64	.5156	17/32	.5312
		24	.5114	33/64	.5156	17/32	.5312
5/8	.6250	11	.5135	17/32	.5312	9/16	.5625	41/64	.6406	21/32	.6562
		18	.5568	37/64	.5781	19/32	.5938
		24	.5739	37/64	.5781	19/32	.5938
11/16	.6875	24	.6364	41/64	.6406	21/32	.6562	45/64	.7031	23/32	.7188
3/4	.7500	10	.6273	21/32	.6562	11/16	.6875	49/64	.7656	25/32	.7812
		16	.6733	11/16	.6875	45/64	.7031
		20	.6887	45/64	.7031	23/32	.7188
13/16	.8125	20	.7512	49/64	.7656	25/32	.7812	53/64	.8281	27/32	.8438
7/8	.8750	9	.7387	49/64	.7656	51/64	.7969	57/64	.8906	29/32	.9062
		14	.7874	13/16	.8125	53/64	.8281
		20	.8137	53/64	.8281	27/32	.8438
15/16	.9375	20	.8762	57/64	.8906	29/32	.9062	61/64	.9531	31/32	.9688
1	1.000	8	.8466	7/8	.8750	59/64	.9219	1-1/64	1.0156	1-1/32	1.0313
		12	.8978	15/16	.9375	61/64	.9531
		20	.9387	61/64	.9531	31/32	.9688

Metric tap drill and clearance drill sizes
Metric Sizes		Tap Drill				Clearance Drill
Screw Size (mm)	Thread Pitch (mm)	Tap Drill				Clearance Drill
		75% Thread for Aluminum, Brass, & Plastics		50% Thread for Steel, Stainless, & Iron		Close Fit		Standard Fit
		Drill Size (mm)	Closest American	Drill Size (mm)	Closest American	Drill Size (mm)	Closest American	Drill Size (mm)	Closest American
M1.5	0.35	1.15	56	1.25	55	1.60	1/16	1.65	52
M1.6	0.35	1.25	55	1.35	54	1.70	51	1.75	50
M1.8	0.35	1.45	53	1.55	1/16	1.90	49	2.00	5/64
M2	0.45	1.55	1/16	1.70	51	2.10	45	2.20	44
M2	0.40	1.60	52	1.75	50	2.10	45	2.20	44
M2.2	0.45	1.75	50	1.90	48	2.30	3/32	2.40	41
M2.5	0.45	2.05	46	2.20	44	2.65	37	2.75	7/64
M3	0.60	2.40	41	2.60	37	3.15	1/8	3.30	30
M3	0.50	2.50	39	2.70	36	3.15	1/8	3.30	30
M3.5	0.60	2.90	32	3.10	31	3.70	27	3.85	24
M4	0.75	3.25	30	3.50	28	4.20	19	4.40	17
M4	0.70	3.30	30	3.50	28	4.20	19	4.40	17
M4.5	0.75	3.75	25	4.00	22	4.75	13	5.00	9
M5	1.00	4.00	21	4.40	11/64	5.25	5	5.50	7/32
	0.90	4.10	20	4.40	17
	0.80	4.20	19	4.50	16
M5.5	0.90	4.60	14	4.90	10	5.80	1	6.10	B
M6	1.00	5.00	8	5.40	4	6.30	E	6.60	G
M6	0.75	5.25	4	5.50	7/32	6.30	E	6.60	G
M7	1.00	6.00	B	6.40	E	7.40	L	7.70	N
M7	0.75	6.25	D	6.50	F	7.40	L	7.70	N
M8	1.25	6.80	H	7.20	J	8.40	Q	8.80	S
M8	1.00	7.00	J	7.40	L	8.40	Q	8.80	S
M9	1.25	7.80	N	8.20	P	9.50	3/8	9.90	25/64
M9	1.00	8.00	O	8.40	21/64	9.50	3/8	9.90	25/64
M10	1.50	8.50	R	9.00	T	10.50	Z	11.00	7/16
	1.25	8.80	11/32	9.20	23/64
	1.00	9.00	T	9.40	U
M11	1.50	9.50	3/8	10.00	X	11.60	29/64	12.10	15/32
M11	1.75	10.30	13/32	10.90	27/64	11.60	29/64	12.10	15/32
M12	1.50	10.50	Z	11.00	7/16	12.60	1/2	13.20	33/64
	1.25	10.80	27/64	11.20	7/16
	2.00	12.10	15/32	12.70	1/2
M14	1.50	12.50	1/2	13.00	33/64	14.75	37/64	15.50	39/64
M14	1.25	12.80	1/2	13.20	33/64	14.75	37/64	15.50	39/64
M15	1.50	13.50	17/32	14.00	35/64	15.75	5/8	16.50	21/32
M15	2.00	14.00	35/64	14.75	37/64	15.75	5/8	16.50	21/32
M16	2.00	14.00	35/64	14.75	37/64	16.75	21/32	17.50	11/16
M16	1.50	14.50	37/64	15.00	19/32	16.75	21/32	17.50	11/16
M17	1.50	15.50	39/64	16.00	5/8	18.00	45/64	18.50	47/64
M17	2.50	15.50	39/64	16.50	41/64	18.00	45/64	18.50	47/64
M18	2.00	16.00	5/8	16.75	21/32	19.00	3/4	20.00	25/32
M18	1.50	16.50	21/32	17.00	43/64	19.00	3/4	20.00	25/32
M19	2.50	16.50	21/32	17.50	11/16	20.00	25/32	21.00	53/64
M20	2.50	17.50	11/16	18.50	23/32	21.00	53/64	22.00	55/64
	2.00	18.00	45/64	18.50	47/64
	1.50	18.50	47/64	19.00	3/4

Choosing Tap Drill and Clearance Drill Sizes

Use this tap drill size chart to find the drill bit diameter needed before cutting internal threads. The standard and metric tables also show clearance drill sizes for holes where the screw or bolt should pass through without engaging threads.

Tap Drill Sizes

A tap drill leaves enough material for the tap to form full, usable threads without overloading the tool or making the hole too tight.

Clearance Drill Sizes

Clearance holes are larger than tapped holes. Use them when a fastener should slide through one part and thread into a second part, nut, or insert.

Inch and Metric Threads

Check the thread system before drilling. Standard taps use inch thread callouts, while metric taps use millimeter sizes and thread pitch.

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