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Tap Drill Size Chart
Complete tap drill chart for metric coarse, metric fine, UNC and UNF threads at 50%, 65% and 75% thread engagement, with inch and metric drill equivalents.
75% thread engagement is the shop default. The exact metric rule is drill = major diameter − pitch; the imperial rule is drill = major − (0.01299 × %thread) / TPI. Click any thread for the full spec sheet.
Metric coarse
| Thread | 75% drill | Inch equivalent | 65% | 50% |
|---|
| M1.6×0.35 | 1.25 mm | 0.0469" (3/64 drill) | 1.3 mm | 1.4 mm |
| M2×0.4 | 1.6 mm | 0.0625" (1/16 drill) | 1.7 mm | 1.7 mm |
| M2.5×0.45 | 2.05 mm | 0.0810" (#46 drill) | 2.1 mm | 2.2 mm |
| M3×0.5 | 2.5 mm | 0.0980" (#40 drill) | 2.6 mm | 2.7 mm |
| M3.5×0.6 | 2.9 mm | 0.1130" (#33 drill) | 3 mm | 3.1 mm |
| M4×0.7 | 3.3 mm | 0.1285" (#30 drill) | 3.4 mm | 3.5 mm |
| M5×0.8 | 4.2 mm | 0.1660" (#19 drill) | 4.3 mm | 4.5 mm |
| M6×1 | 5 mm | 0.1960" (#9 drill) | 5.2 mm | 5.4 mm |
| M7×1 | 6 mm | 0.2380" (B drill) | 6.2 mm | 6.4 mm |
| M8×1.25 | 6.8 mm | 0.2660" (H drill) | 6.9 mm | 7.2 mm |
| M10×1.5 | 8.5 mm | 0.3320" (Q drill) | 8.7 mm | 9 mm |
| M12×1.75 | 10.2 mm | 0.4040" (Y drill) | 10.5 mm | 10.9 mm |
| M14×2 | 12 mm | 0.4688" (15/32 drill) | 12.3 mm | 12.7 mm |
| M16×2 | 14 mm | 0.5469" (35/64 drill) | 14.3 mm | 14.7 mm |
| M18×2.5 | 15.5 mm | 0.6094" (39/64 drill) | 15.9 mm | 16.4 mm |
| M20×2.5 | 17.5 mm | 0.6875" (11/16 drill) | 17.9 mm | 18.4 mm |
| M22×2.5 | 19.5 mm | 0.7656" (49/64 drill) | 19.9 mm | 20.4 mm |
| M24×3 | 21 mm | 0.8281" (53/64 drill) | 21.5 mm | 22.1 mm |
| M27×3 | 24 mm | 0.9375" (15/16 drill) | 24.5 mm | 25.1 mm |
| M30×3.5 | 26.5 mm | 1.0469" (67/64 drill) | 27 mm | 27.5 mm |
| M33×3.5 | 29.5 mm | 1.1562" (37/32 drill) | 30 mm | 30.5 mm |
| M36×4 | 32 mm | 1.2656" (81/64 drill) | 32.5 mm | 33.5 mm |
| M39×4 | 35 mm | 1.3750" (11/8 drill) | 35.5 mm | 36.5 mm |
| M42×4.5 | 37.5 mm | 1.4688" (47/32 drill) | 38 mm | 39 mm |
| M45×4.5 | 40.5 mm | 1.5938" (51/32 drill) | 41 mm | 42 mm |
| M48×5 | 43 mm | 1.6875" (27/16 drill) | 44 mm | 45 mm |
| M52×5 | 47 mm | 1.8438" (59/32 drill) | 48 mm | 49 mm |
| M56×5.5 | 50.5 mm | 1.9844" (127/64 drill) | 51.5 mm | 52.5 mm |
| M60×5.5 | 54.5 mm | no standard inch drill | 55.5 mm | 56.5 mm |
| M64×6 | 58 mm | no standard inch drill | 59 mm | 60 mm |
Metric fine
| Thread | 75% drill | Inch equivalent | 65% | 50% |
|---|
| M3×0.35 | 2.65 mm | 0.1040" (#37 drill) | 2.7 mm | 2.8 mm |
| M4×0.5 | 3.5 mm | 0.1360" (#29 drill) | 3.6 mm | 3.7 mm |
| M5×0.5 | 4.5 mm | 0.1770" (#16 drill) | 4.6 mm | 4.7 mm |
| M6×0.75 | 5.25 mm | 0.2055" (#5 drill) | 5.4 mm | 5.5 mm |
| M8×1 | 7 mm | 0.2770" (J drill) | 7.2 mm | 7.4 mm |
| M8×0.75 | 7.25 mm | 0.2812" (9/32 drill) | 7.4 mm | 7.5 mm |
| M10×1.25 | 8.8 mm | 0.3480" (S drill) | 8.9 mm | 9.2 mm |
| M10×1 | 9 mm | 0.3580" (T drill) | 9.2 mm | 9.4 mm |
| M12×1.5 | 10.5 mm | 0.4130" (Z drill) | 10.7 mm | 11 mm |
| M12×1.25 | 10.8 mm | 0.4219" (27/64 drill) | 10.9 mm | 11.2 mm |
| M14×1.5 | 12.5 mm | 0.4844" (31/64 drill) | 12.7 mm | 13 mm |
| M16×1.5 | 14.5 mm | 0.5781" (37/64 drill) | 14.7 mm | 15 mm |
| M18×1.5 | 16.5 mm | 0.6562" (21/32 drill) | 16.7 mm | 17 mm |
| M20×1.5 | 18.5 mm | 0.7344" (47/64 drill) | 18.7 mm | 19 mm |
| M22×1.5 | 20.5 mm | 0.8125" (13/16 drill) | 20.7 mm | 21 mm |
| M24×2 | 22 mm | 0.8594" (55/64 drill) | 22.3 mm | 22.7 mm |
| M27×2 | 25 mm | 0.9844" (63/64 drill) | 25.3 mm | 25.7 mm |
| M30×2 | 28 mm | 1.1094" (71/64 drill) | 28.5 mm | 28.5 mm |
| M33×2 | 31 mm | 1.2188" (39/32 drill) | 31.5 mm | 31.5 mm |
| M36×3 | 33 mm | 1.2969" (83/64 drill) | 33.5 mm | 34 mm |
| M39×3 | 36 mm | 1.4219" (91/64 drill) | 36.5 mm | 37 mm |
| M42×3 | 39 mm | 1.5312" (49/32 drill) | 39.5 mm | 40 mm |
| M45×3 | 42 mm | 1.6562" (53/32 drill) | 42.5 mm | 43 mm |
| M48×3 | 45 mm | 1.7656" (113/64 drill) | 45.5 mm | 46 mm |
| M52×3 | 49 mm | 1.9219" (123/64 drill) | 49.5 mm | 50 mm |
| M56×4 | 52 mm | no standard inch drill | 52.5 mm | 53.5 mm |
| M60×4 | 56 mm | no standard inch drill | 56.5 mm | 57.5 mm |
| M64×4 | 60 mm | no standard inch drill | 60.5 mm | 61.5 mm |
Unified coarse (UNC)
Unified fine (UNF)