Tap Drill Chart & Thread Size

The drill size for any tap, in your pocket, with no signal needed.

Search the thread the way you say it — M6, m6x1, 1/4, 1/4-20, 10-24, #10 — and read the tap drill straight off the screen. Every size is given in millimetres, and the inch threads also name the fraction, number or letter stamped on the drill, so you can pick it up without converting anything.

THE CHART, FREE AND COMPLETE
• Metric coarse, M1.6 to M24
• Metric fine, the pitches a shop actually stocks
• UNC and UNF, #0 to 1"
• Tap drill and clearance drill for each
• Pitch, or threads per inch on the inch threads
• Works with no signal, no account and no sign-in

WHERE THE NUMBERS COME FROM
These are the published sizes from the standard tables, not a formula rounded off. M12 x 1.75 reads 10.2 mm, which is the drill that exists, rather than the 10.30 the arithmetic gives. Metric clearance holes follow ISO 273. Where the published close-fit tables for numbered machine screws disagree between sources, the row simply leaves the clearance out rather than printing a number we cannot stand behind.

THE BENCH, ONE OPTIONAL PAYMENT
Three things the chart cannot answer:
• Thread depth — the drill for any percentage from 50% to 100%, for soft metal, deep holes or thin sheet, and the reverse: tell it the drill you already have and it tells you the thread you would be left with.
• Pipe threads — NPT, BSPT and BSPP, with each one saying whether it seals on the thread or on a washer.
• Drill index — every fraction, number, letter and metric size in one searchable list, so you can cross one index to another.

One payment. No subscription, no adverts, no account, nothing to restore every month. The chart stays free whether you buy it or not.

Built for anyone who taps a hole and would rather not snap the tap: machinists, fitters, mechanics, model engineers, maintenance crews, and anyone who has ever stood at a drill index trying to remember whether it was the 5.0 or the 5.5.