Drill size chart: number #1–#80, letter A–Z, fractional 1/64–1 in and metric drills in decimal inches and mm (ASME B94.11M)

sizes

205 in table

Notes

• Drill sizes come in four series. Number drills #1 to #80 (#1 = 0.2280 in is the largest, #80 = 0.0135 in the smallest; CNCCookbook notes ASME B94.11M numbers run to #97 but sizes past #80 are seldom seen), letter drills A to Z (A = 0.2340 in to Z = 0.4130 in), fractional drills from 1/64 in in 1/64 in steps, and metric drills. The decimal inch values for the number, letter and fractional drills are the Starrett table as printed; the mm column is that inch value × 25.4 rounded to 0.001 mm (the fractional mm are the exact fraction × 25.4). The metric rows are the standard mm sizes with the inch value computed as mm ÷ 25.4.
• Cross-checks: Newman Tools lists #1 = 0.2280, #40 = 0.0980, #80 = 0.0135, A = 0.234, E = 0.250, Z = 0.413; Xometry lists #8 = 0.199, A = 0.234 and 3.20 mm = 0.126 in; AIMS Industrial lists #80 = 0.343 mm, #1 = 5.791 mm, A = 5.944 mm and Z = 10.490 mm. All agree with the table here. The metric block is a short list of whole and half millimetres for convenience, not every metric drill size.
• Use: a drill is the size of the hole it cuts only approximately. Real holes run a little over; the clearance and tap-drill tables on thread-reference-tap-drills-clearance give the drill chosen for a thread or a screw. This page is the size lookup, not a hole-fit recommendation. Not here: drill point angle, flute length series (jobber, stub, screw-machine), taps, reamers and fractional drills above 1 in.
• No files: a drill is not a mating geometry on its own and a plate of holes at drill sizes would be a stand-in. The hole-size gauges for specific fasteners (rivet nuts, cable glands, PEM nuts) are on their own pages.

Drill size chart: number #1–#80, letter A–Z, fractional 1/64–1 in… size chart

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

Plain text: sheet.txt · JSON: /api/geometry?object=drill-size-index-number-letter-fraction

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