M4 × 0.7 tap drill size

3.30 mm drill — or #30 (0.1285 in) = 81% thread

M4 coarse series, 0.7 mm pitch. Tap drill Ø = nominal − pitch = 4 − 0.7 = 3.30 mm (≈77% thread, the standard chart value).

Rounding to your nearest stock drill moves the thread percentage only a few points. Cut taps only — roll-form taps need a larger hole. Verify before you cut.

Need a different thread percentage? Open the tap drill calculator · Metric tap chart · All calculators