Drill Bit Imperial to Metric Equivalents

Drill Size (Inch)	Drill Size (A‑Z)	Tap	Inch (Dec)	mm	Closest Metric (mm)	Twist	Brad	Forstner
1/32			.0312	0.794	0.8
			.0394	1.000	1.0
3/64			.0469	1.191	1.2
1/16			.0625	1.587	1.6
5/64			.0781	1.984	2.0
		2.5mm x 0.45	.0787	2.000	2.0
3/32			.0937	2.381	2.4
		3mm x 0.50	.0984	2.500	2.5
7/64			.1093	2.778	2.8
			.1181	3.000	3.0
1/8			.1250	3.175	3.2
		4mm x 0.70		3.400	3.4
9/64			.1406	3.572	3.6
5/32			.1562	3.969	4.0
			.1575	4.000	4.0
		5mm x 0.80		4.000	4.3
11/64			.1719	4.366	4.4
3/16			.1875	4.762	4.8
			.1968	5.000	5.0
13/64		UNC 1/4" x 20	.2031	5.159	5.2
		6mm x 1.00		5.200	5.2
7/32			.2187	5.556	5.6
	A		.2340	5.944	5.9
15/64			.2344	5.953	6.0
			.2632	6.000	6.0
	B		.2380	6.045	6.0
		7mm x 1.00		6.100	6.1
	C		.2420	6.147	6.1
	D		.2460	6.248	6.2
1/4	E		.2500	6.350	6.4
	F	UNC 5/16" x 18	.2570	6.528	6.5
	G		.2610	6.629	6.6
17/64			.2656	6.747	6.7
	H		.2660	6.756	6.8
			.2677	6.800	6.8
		8mm x 1.25		6.900	6.9
	I	UNF 5/16" x 24	.2720	6.909	6.9
			.2756	7.000	7.0
	J		.2770	7.036	7.0
		8mm x 1.00		7.100	7.1
	K		.2810	7.137	7.1
9/32			.2812	7.144	7.1
	L		.2900	7.366	7.4
	M		.2950	7.493	7.5
19/64			.2968	7.541	7.5
	N		.3020	7.671	7.7
5/16		UNC 3/8 x 16	.3125	7.937	8.0
			.3150	8.000	8.0
	O		.3160	8.026	8.0
	P		.3230	8.204	8.2
21/64			.3281	8.334	8.2
	Q	UNF 3/8" x 24	.3320	8.433	8.4
			.3346	8.500	8.5
	R		.3390	8.611	8.6
		10mm x 1.50		8.700	8.7
11/32			.3437	8.731	8.7
	S		.3480	8.839	8.8
		10mm x 1.25		8.900	8.9
			.3543	9.000	9.0
	T		.3580	9.093	9.1
		10mm x 1.00		9.100	9.1
23/64			.3594	9.128	9.1
	U	UNC 7/16" x 14	.3680	9.347	9.3
			.3740	9.500	9.5
3/8			.3750	9.525	9.5
	V		.3770	9.576	9.6
	W		.3860	9.804	9.8
25/64		UNF 7/16" x 20	.3906	9.922	9.9
			.3937	10.000	10.0
	X		.3970	10.080	10.1
	Y		.4040	10.260	10.3
13/32			.4062	10.319	10.3
	Z		.4130	10.490	10.5
		12mm x 1.75	.4133	10.500	10.5
		12mm x 1.50		10.700	10.7
27/64		UNC 1/2" x 13	.4219	10.715	10.7
			.4331	11.000	11.0
7/16			.4375	11.113	11.1
29/64		UNF 1/2" x 20	.4531	11.509	11.5
15/32		1/2" x 28	.4687	11.906	11.9
			.4724	12.000	12.0
31/64			.4844	12.303	12.3
		14mm x 1.00	.4921	12.500	12.5
1/2			.5000	12.700	12.7
			.5118	13.000	13.0
			.5512	14.000	14.0
			.5906	15.000	15.0
			.6299	16.000	16.0
			.7087	18.000	18.0
			.7874	20.000	20.0
			.8268	21.000	21.0
			.8661	22.000	22.0
			.9843	25.000	25.0
			1.0236	26.000	26.0
			1.1024	28.000	28.0
			1.1811	30.000	30.0
			1.3780	35.000	35.0
			1.5748	40.000	40.0
			1.7717	45.000	45.0
			1.9685	50.000	50.0