Fractional drill and tap chart with metric and decimal equivalents

Electrical Advice From an Experienced Professional

Fractional Drill & Tap Sizes with Metric and Decimal Equivalents

Drill sizes from 1/64" to 1"and from .1 millimeter to 25.40000 millimeters

Minimum and maximum drill sizes are indicated for many taps. A smaller hole will have tighter threads, but will be more work to tap in hard materials. A smaller hole is probably a good idea in soft metals such as copper or brass. Not responsible for errors and omissions regarding the content of this page

1/64

3/64

5/64

7/64

9/64

11/64

13/64

15/64

17/64

19/64

21/64

23/64

25/64

27/64

29/64

31/64

33/64

35/64

37/64

39/64

41/64

43/64

45/64

47/64

49/64

51/64

53/64

55/64

57/64

59/64

61/64

63/64

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	ISO Pitch	Fine Pitch	Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	ISO Pitch	Fine Pitch
	.003937	.1						.208661	5.3
	.0059055	.15						.2090		4
	.007874	.2						.212598	5.4
	.0098425	.25						.2130		3	1/4-28
	.011811	.3						.214			1/4-28
	.0135		80					.216535	5.5
	.0145		79				7/32	.218750	5.55625
1/64	.015625	.39688						.220472	5.6
	.015748	.4						.2210		2
	.0160		78					.224409	5.7
	.0177165	.45						.2263775	5.75
	.0180		77					.2280		1
	.019685	.5						.228346	5.8
	.0200		76					.232283	5.9
	.0210		75					.2340		A
	.0216535	.55					15/64	.234375	5.95313
	.0225		74					.236220	M6			1.0
	.023622	.6						.2380		B
	.0240		73					.240157	6.1
	.0250		72					.2420		C
	.0255905	.65						.244094	6.2
	.0260		71					.2460	6.25	D
	.0280		70					.248031	6.3
	.027559	.7					1/4	.250000	6.35000	E
	.0292		69					.251968	6.4
	.0295275	.75						.255905	6.5
	.0310		68					.2570		F	5/16-18
1/32	.031250	.79375						.259842	6.6
	.031496	.8						.2610		G	5/16-18
	.0320		67					.263779	6.7
	.0330		66				17/64	.265625	6.74688
	.0334645	.85						.2657475	6.75
	.0350		65					.2660		H	5/16-24
	.035433	.9						.267716	6.8
	.0360		64					.271			5/16-24
	.0370		63					.271653	6.9
	.0374015	.95						.2720		I	5/16-24
	.0380		62					.27559	7
	.0390		61					.2770		J
	.03937	1						.279527	7.1
	.0400		60					.2811		K
	.0410		59				9/32	.281250	7.14375
	.0413385	1.05						.283464	7.2
	.0420		58					.2854325	7.25
	.0430		57					.287401	7.3
	.043307	1.1						.2900		L
	.0452755	1.15						.291338	7.4
	.0465		56	0-80				.2950		M
3/64	.046875	1.19063		0-80				.295275	7.5
	.047244	1.2					19/64	.296875	7.54063
	.048			0-80				.299212	7.6
	.0492125	1.25						.3020		N
	.051181	1.3						.303149	7.7
	.0520		55					.3051175	7.75
	.0531495	1.35						.307086	7.8
	.0550		54					.311023	7.9
	.055118	1.4						.312			3/8-16
	.057			1-64			5/16	.312500	7.93750		3/8-16
	.0570865	1.45						.31496	M8			1.25
	.059			1-72				.3160		O	3/8-16
	.059055	1.5						.318897	8.1
	.0595		53	1-72				.322834	8.2
	.0610235	1.55						.3230		P
1/16	.062500	1.58750						.3248025	8.25
	.062992	1.6						.326771	8.3
	.0635		52				21/64	.328125	8.33438		3/8-24
	.0649605	1.65						.330708	8.4
	.066929	1.7						.3320		Q	3/8-24
	.0670		51	2-56				.333			3/8-24
	.068			2-56				.334645	8.5
	.0688975	1.75						.338582	8.6
	.0700		50	2-64				.3390		R
	.070866	1.8						.342519	8.7
	.0728345	1.85					11/32	.343750	8.73125
	.0730		49					.3444875	8.75
	.074803	1.9						.346456	8.8
	.0760		48					.3480		S
	.0767715	1.95						.350393	8.9
	.078			3-48				.354330	9
5/64	.078125	1.98438		3-48				.3580		T
	.0785		47	3-48				.358267	9.1
	.07874	M2			.4		23/64	.359375	9.12813		7/16-14
	.0807085	2.05						.362204	9.2
	.0810		46	3-56				.3641725	9.25
	.0820		45	3-56				.366			7/16-14
	.082677	2.1						.366141	9.3
	.0846455	2.15						.3680		U	7/16-14
	.0860		44	4-40				.370078	9.4
	.086614	2.2						.374015	9.5
	.087			4-40			3/8	.375000	9.52500
	.0885825	2.25						.3770		V
	.0890		43	4-40				.377952	9.6
	.090551	2.3						.381889	9.7
	.091			4-48				.385826	9.8
	.0925195	2.35						.3860		W	7/16-20
	.0935		42	4-48				.388			7/16-20
3/32	.093750	2.38125		4-48				.389763	9.9
	.094488	2.4					25/64	.390625	9.92188		7/16-20
	.0960		41					.393700	M10			1.75	1.25
	.0964565	2.45						.3970		X
	.0980		40	5-40				.4040		Y
	.098425	2.5					13/32	.406250	10.31875
	.0995		39	5-40				.4130		Z
	.100			5-40				.413385	10.5
	.1015		38	5-44			27/64	.421875	10.71563		1/2-13
	.102			5-44				.423			1/2-13
	.102362	2.6						.433070	11
	.1040		37				7/16	.437500	11.11250
	.106299	2.7						.450			1/2-20
	.1065		36	6-32				.452755	11.5
	.107			6-32			29/64	.453125	11.50938		1/2-20
	.1082675	2.75					15/32	.468750	11.90625
7/64	.109375	2.77813		6-32				.472440	M12			1.75	1.25
	.1100		35	6-32				.479			9/16-12
	.110236	2.8					31/64	.484375	12.30313		9/16-12
	.1110		34	6-40				.492125	12.5
	.1130		33	6-40			1/2"	.500000"	12.70000		9/16-18
	.114173	2.9						.507			9/16-18
	.1160		32	6-40				.511810	13
	.11811	M3			.5		33/64	.515625	13.09688
	.1200		31				17/32	.531250	13.49375		5/8-11
	.122047	3.1						.531495	13.5
1/8	.125000	3.17500						.534			5/8-11
	.125984	3.2					35/64	.546875	13.89063
	.1279525	3.25						.551180	M14			2.0	1.5
	.1285	3.26390	30				9/16	.562500	14.28750		5/8-18
	.129921	3.3						.569			5/8-18
	.133			8-32				.570865	14.5
	.133858	3.4					37/64	.578125	14.68438
	.1360	3.45440	29	8-36				.590550	15
	.137795	3.5					19/32	.59375	15.08125
	.1405	3.56870	28				39/64	.609375	15.47813
9/64	.140625	3.571875						.610235	15.5
	.141732	3.6					5/8	.625	15.87500
	.1440		27					.629920	M16			2.0	1.5
	.145669	3.7					41/64	.640625	16.27188
	.1470		26	10-24				.649605	16.5
	.1476375	3.75						.650			3/4-10
	.148			10-24			21/32	.65625	16.66875		3/4-10
	.1495		25	10-24				.669290	17
	.149606	3.8					43/64	.671875	17.06563
	.1520		24	10-24			11/16	.6875	17.46250		3/4-16
	.153543	3.9						.688			3/4-16
	.1540		23					.688975	17.5
5/32	.156250	3.96875		10-32			45/64	.703125	17.85938
	.1570		22	10-32				.708660	M18			2.5	1.5
	.15748	M4			.7		23/32	.71875	18.25625
	.1590		21	10-32				.728345	18.5
	.1610		20				47/64	.734375	18.65313
	.161417	4.1						.748030	19
	.165354	4.2					3/4	.75	19.05000
	.1660		19					.764			7/8-9
	.1673225	4.25					49/64	.765625	19.44668		7/8-9
	.169291	4.3						.767715	19.5
	.1695		18				25/32	.78125	19.84375
11/64	.171875	4.36563		12-24				.787400	M20			2.5	1.5
	.1730		17	12-24			51/64	.796875	20.24063		7/8-14
	.173228	4.4						.804			7/8-14
	.174			12-24			13/16	.8125	20.63750
	.1770		16	12-28				.826770	21
	.177165	4.5					53/64	.828125	21.03438
	.1800		15	12-28			27/32	.84375	21.43125
	.181102	4.6						.846455	21.5


	.1820		14	12-28			55/64	.859375	21.83813
	.1850	4.7	13					.866140	22
	.1870075	4.75					7/8	.875	22.22500		1"-8
3/16	.187500	4.76250						.885825	22.5
	.188976	4.8	12				57/64	.890625	22.62187		1"-8
	.1910		11					.905510	23
	.192913	4.9					29/32	.90625	23.01875
	.1935		10				59/64	.921875	23.41563		1"-12, 1"-14
	.1960		9	1/4-20				.925195	23.5
	.196850	M5			.8			.929			1"-14
	.1990		8	1/4-20			15/16	.9375	23.81250		1"-14
	.200			1/4-20				.94488	M24			3.0	1.5
	.200787	5.1					61/64		24.209
13/64	.203125	5.15938		1/4-20				.964565	24.5
	.204724	5.2						.982	25		1 1/8"-7
	.2055		5				63/64	.984375	25.00312		1 1/8"-7
	.2066925	5.25					1"	1.000"	25.40000		1 1/8"-7

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	ISO Pitch	Fine Pitch	Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	ISO Pitch	Fine Pitch