METRIC TAP DRILL CHART

Metric tap drill chart according to ISO 2306:1972 standard for ISO metric threads. Dimension are in millimetres.

Coarse Pitch Thread							Drill size (mm)
Tap Size	Basic Major Dia.	Thread Pitch	Minor diameter for class
			5H max.	6H max.	7H max.	5H, 6H, 7H min
M1.6 x 0.35	1.6	0.35	1.301	1.321	-	1.221	1.25
M2 x 0.4	2	0.4	1.657	1.679	-	1.567	1.60
M2.5 x 0.45	2.5	0.45	2.113	2.138	-	2.013	2.05
M3 x 0.5	3	0.5	2.571	2.599	2.639	2.459	2.50
M3.5* x 0.6	3.5	0.6	2.975	3.010	3.050	2.850	2.90
M4 x 0.7	4	0.7	3.382	3.422	3.466	3.242	3.30
M5 x 0.8	5	0.8	4.294	4.334	4.384	4.134	4.20
M6 x 1	6	1	5.107	5.153	5.217	4.917	5.00
M8 x 1.25	8	1.25	6.859	6.912	6.982	6.647	6.80
M10 x 1.5	10	1.5	8.612	8.676	8.751	8.376	8.50
M12 x 1.75	12	1.75	10.371	10.441	10.531	10.106	10.20
M14* x 2	14	2	12.135	12.210	12.310	11.835	12.00
M16 x 2	16	2	14.135	14.210	14.310	13.835	14.00
M18* x 2.5	18	2.5	15.649	15.744	15.854	15.294	15.50
M20 x 2.5	20	2.5	17.649	17.744	17.854	17.294	17.50
M22* x 2.5	22	2.5	19.649	19.744	19.854	19.294	19.50
M24 x 3	24	3	21.152	21.252	21.382	20.752	21.00
M27* x 3	27	3	24.152	24.252	24.382	23.752	24.00
M30 x 3.5	30	3.5	26.661	26.771	26.921	26.211	26.50
M33* x 3.5	33	3.5	29.661	29.771	29.921	29.211	29.50
M36 x 4	36	4	32.145	32.270	32.420	31.670	32.00
M39* x 4	39	4	35.145	35.270	35.420	34.670	35.00
M42 x 4.5	42	4.5	37.659	37.799	37.979	37.129	37.50
M45* x 4.5	45	4.5	40.659	40.799	40.979	40.129	40.50
M48 x 5	48	5	43.147	43.297	43.487	42.587	43.00
M52* x 5	52	5	47.147	47.297	47.487	46.587	47.00
M56 x 5.5	56	5.5	50.646	50.796	50.996	50.046	50.50

Note : * Non-preferred threads according to standard.

Fine Pitch Thread							Drill size (mm)
Tap Size	Basic Major Dia.	Thread Pitch	Minor diameter for class
			5H max.	6H max.	7H max.	5H, 6H, 7H min
M8 x 1	8	1	7.107	7.153	7.217	6.917	7.00
M10 x 1	10	1	9.107	9.153	9.217	8.917	9.00
M10* x 1.25	10	1.25	8.859	8.912	8.982	8.647	8.80
M12* x 1.25	12	1.25	10.859	10.912	10.982	10.647	10.80
M12 x 1.5	12	1.5	10.612	10.676	10.751	10.376	10.50
M14* x 1.5	14	1.5	12.612	12.676	12.751	12.376	12.50
M16 x 1.5	16	1.5	14.612	14.676	14.751	14.376	14.50
M18* x 1.5	18	1.5	16.612	16.676	16.751	16.376	16.50
M20 x 1.5	20	1.5	18.612	18.676	18.751	18.376	18.50
M20* x 2	20	2	18.135	18.210	18.310	17.835	18.00
M22* x 1.5	22	1.5	20.612	20.676	20.751	20.376	20.50
M24 x 2	24	2	22.135	22.210	22.310	21.835	22.00
M27* x 2	27	2	25.135	25.210	25.310	24.835	25.00
M30 x 2	30	2	28.135	28.210	28.310	27.835	28.00
M33* x 2	33	2	31.135	31.210	31.310	30.835	31.00
M36 x 3	36	3	33.152	33.252	33.382	32.752	33.00
M39* x 3	39	3	36.152	36.252	36.382	36.752	36.00
M42 x 3	42	3	39.152	39.252	39.382	38.752	39.00
M45* x 3	45	3	42.152	42.252	42.382	41.752	42.00
M48 x 3	48	3	45.152	45.252	45.382	44.752	45.00
M52* x 4	52	4	48.145	48.270	48.420	47.670	48.00

Note : * Non-preferred threads according to standard.

Supplements:

Link	Usage
Metric tap drill size calculator	Calculator form of the metric tap drill chart.

Reference: