Engineering · Calculators

Tap drill lookup.

Cut-tap drill lookup for UNC, UNF and metric threads. Not for forming taps or threaded inserts. Verify the selected tap manufacturer's hole range, material, thread class and actual drilled hole.

SearchSeries

Size	Series	Major Ø	Pitch / TPI	Tap drill	Drill
#1-64	UNC	0.0730″1.85 mm	64 TPI	0.0595″1.51 mm	#53
#2-56	UNC	0.0860″2.18 mm	56 TPI	0.0700″1.78 mm	#50
#3-48	UNC	0.0990″2.51 mm	48 TPI	0.0785″1.99 mm	#47
#4-40	UNC	0.1120″2.84 mm	40 TPI	0.0890″2.26 mm	#43
#5-40	UNC	0.1250″3.17 mm	40 TPI	0.1015″2.58 mm	#38
#6-32	UNC	0.1380″3.51 mm	32 TPI	0.1065″2.71 mm	#36
#8-32	UNC	0.1640″4.17 mm	32 TPI	0.1360″3.45 mm	#29
#10-24	UNC	0.1900″4.83 mm	24 TPI	0.1495″3.80 mm	#25
#12-24	UNC	0.2160″5.49 mm	24 TPI	0.1770″4.50 mm	#16
1/4-20	UNC	0.2500″6.35 mm	20 TPI	0.2010″5.11 mm	#7
5/16-18	UNC	0.3125″7.94 mm	18 TPI	0.2570″6.53 mm	F
3/8-16	UNC	0.3750″9.52 mm	16 TPI	0.3125″7.94 mm	5/16
7/16-14	UNC	0.4375″11.11 mm	14 TPI	0.3680″9.35 mm	U
1/2-13	UNC	0.5000″12.70 mm	13 TPI	0.4219″10.72 mm	27/64
9/16-12	UNC	0.5625″14.29 mm	12 TPI	0.4844″12.30 mm	31/64
5/8-11	UNC	0.6250″15.88 mm	11 TPI	0.5313″13.49 mm	17/32
3/4-10	UNC	0.7500″19.05 mm	10 TPI	0.6563″16.67 mm	21/32
7/8-9	UNC	0.8750″22.22 mm	9 TPI	0.7656″19.45 mm	49/64
1-8	UNC	1.0000″25.40 mm	8 TPI	0.8750″22.22 mm	7/8
1 1/8-7	UNC	1.1250″28.57 mm	7 TPI	0.9844″25.00 mm	63/64
1 1/4-7	UNC	1.2500″31.75 mm	7 TPI	1.1094″28.18 mm	1 7/64
1 1/2-6	UNC	1.5000″38.10 mm	6 TPI	1.3281″33.73 mm	1 21/64
#0-80	UNF	0.0600″1.52 mm	80 TPI	0.0469″1.19 mm	3/64
#1-72	UNF	0.0730″1.85 mm	72 TPI	0.0595″1.51 mm	#53
#2-64	UNF	0.0860″2.18 mm	64 TPI	0.0700″1.78 mm	#50
#3-56	UNF	0.0990″2.51 mm	56 TPI	0.0820″2.08 mm	#45
#4-48	UNF	0.1120″2.84 mm	48 TPI	0.0935″2.37 mm	#42
#5-44	UNF	0.1250″3.17 mm	44 TPI	0.1040″2.64 mm	#37
#6-40	UNF	0.1380″3.51 mm	40 TPI	0.1130″2.87 mm	#33
#8-36	UNF	0.1640″4.17 mm	36 TPI	0.1360″3.45 mm	#29
#10-32	UNF	0.1900″4.83 mm	32 TPI	0.1590″4.04 mm	#21
#12-28	UNF	0.2160″5.49 mm	28 TPI	0.1820″4.62 mm	#14
1/4-28	UNF	0.2500″6.35 mm	28 TPI	0.2130″5.41 mm	#3
5/16-24	UNF	0.3125″7.94 mm	24 TPI	0.2720″6.91 mm	I
3/8-24	UNF	0.3750″9.52 mm	24 TPI	0.3320″8.43 mm	Q
7/16-20	UNF	0.4375″11.11 mm	20 TPI	0.3906″9.92 mm	25/64
1/2-20	UNF	0.5000″12.70 mm	20 TPI	0.4531″11.51 mm	29/64
9/16-18	UNF	0.5625″14.29 mm	18 TPI	0.5156″13.10 mm	33/64
5/8-18	UNF	0.6250″15.88 mm	18 TPI	0.5781″14.68 mm	37/64
3/4-16	UNF	0.7500″19.05 mm	16 TPI	0.6875″17.46 mm	11/16
7/8-14	UNF	0.8750″22.22 mm	14 TPI	0.8125″20.64 mm	13/16
1-12	UNF	1.0000″25.40 mm	12 TPI	0.9219″23.42 mm	59/64
1 1/4-12	UNF	1.2500″31.75 mm	12 TPI	1.1719″29.77 mm	1 11/64
1 1/2-12	UNF	1.5000″38.10 mm	12 TPI	1.4219″36.12 mm	1 27/64
M2	MC	0.0787″2.00 mm	0.4 mm	0.0630″1.60 mm	1.6 mm
M2.5	MC	0.0984″2.50 mm	0.45 mm	0.0807″2.05 mm	2.05 mm
M3	MC	0.1181″3.00 mm	0.5 mm	0.0984″2.50 mm	2.5 mm
M4	MC	0.1575″4.00 mm	0.7 mm	0.1299″3.30 mm	3.3 mm
M5	MC	0.1969″5.00 mm	0.8 mm	0.1654″4.20 mm	4.2 mm
M6	MC	0.2362″6.00 mm	1 mm	0.1969″5.00 mm	5.0 mm
M8	MC	0.3150″8.00 mm	1.25 mm	0.2677″6.80 mm	6.8 mm
M10	MC	0.3937″10.00 mm	1.5 mm	0.3346″8.50 mm	8.5 mm
M12	MC	0.4724″12.00 mm	1.75 mm	0.4016″10.20 mm	10.2 mm
M14	MC	0.5512″14.00 mm	2 mm	0.4724″12.00 mm	12.0 mm
M16	MC	0.6299″16.00 mm	2 mm	0.5512″14.00 mm	14.0 mm
M20	MC	0.7874″20.00 mm	2.5 mm	0.6890″17.50 mm	17.5 mm
M24	MC	0.9449″24.00 mm	3 mm	0.8268″21.00 mm	21.0 mm
M30	MC	1.1811″30.00 mm	3.5 mm	1.0433″26.50 mm	26.5 mm
M3 × 0.35	MF	0.1181″3.00 mm	0.35 mm	0.1043″2.65 mm	2.65 mm
M4 × 0.5	MF	0.1575″4.00 mm	0.5 mm	0.1378″3.50 mm	3.5 mm
M5 × 0.5	MF	0.1969″5.00 mm	0.5 mm	0.1772″4.50 mm	4.5 mm
M6 × 0.75	MF	0.2362″6.00 mm	0.75 mm	0.2067″5.25 mm	5.25 mm
M8 × 1.0	MF	0.3150″8.00 mm	1 mm	0.2756″7.00 mm	7.0 mm
M10 × 1.25	MF	0.3937″10.00 mm	1.25 mm	0.3465″8.80 mm	8.8 mm
M12 × 1.25	MF	0.4724″12.00 mm	1.25 mm	0.4232″10.75 mm	10.75 mm
M12 × 1.5	MF	0.4724″12.00 mm	1.5 mm	0.4134″10.50 mm	10.5 mm
M14 × 1.5	MF	0.5512″14.00 mm	1.5 mm	0.4921″12.50 mm	12.5 mm
M16 × 1.5	MF	0.6299″16.00 mm	1.5 mm	0.5709″14.50 mm	14.5 mm
M20 × 1.5	MF	0.7874″20.00 mm	1.5 mm	0.7283″18.50 mm	18.5 mm

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Cut taps, not forming taps

Percentage thread is not a universal 75% for these rounded drill sizes, and is not axial engagement length. Forming taps and threaded inserts require different preparation. The actual hole, tap geometry, material and thread class govern selection.

For form (roll) taps

Form taps need a different pre-tap hole because material flows into the threads. Do not apply a fixed offset to this cutting-tap table. Use the tap manufacturer's preparation diameter and tolerance for the specific thread, material and tap.

Keep exploring

Related tools & references

Thread specs reference→

Pitch, major/minor diameters, and classes for UN and metric.

Drill size chart→

Decimal equivalents for number, letter, and fractional drills.

Clearance hole chart→

Through-hole sizes for the matching fastener.

Thread engagement calculator→

Minimum tapped depth so threads don't strip.

Bolt torque calculator→

Tightening torque for the fastener you're tapping for.

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