Tap Drill Size Calculator
Find the correct tap drill size for any metric or imperial thread. Pick a thread from the ISO metric coarse/fine and UNC/UNF tables (or enter a custom major diameter and pitch), set the thread engagement you want, and get the theoretical hole size plus the nearest real drill — metric, fractional, number or letter — with the engagement it actually delivers.
Authorizations
Bearer authentication header of the form Bearer <token>, where <token> is your auth token.
Body
Thread Standard
metric, imperial, custom Metric Thread
M1.6x0.35, M2x0.4, M2.5x0.45, M3x0.5, M3.5x0.6, M4x0.7, M5x0.8, M6x1, M8x1.25, M10x1.5, M12x1.75, M14x2, M16x2, M18x2.5, M20x2.5, M22x2.5, M24x3, M27x3, M30x3.5, M33x3.5, M36x4, M4x0.5, M5x0.5, M6x0.75, M8x1, M10x1.25, M10x1, M12x1.5, M12x1.25, M14x1.5, M16x1.5, M18x1.5, M20x1.5, M22x1.5, M24x2, M27x2, M30x2, M33x2, M36x3 Imperial Thread
#1-64-UNC, #2-56-UNC, #3-48-UNC, #4-40-UNC, #5-40-UNC, #6-32-UNC, #8-32-UNC, #10-24-UNC, #12-24-UNC, 1/4-20-UNC, 5/16-18-UNC, 3/8-16-UNC, 7/16-14-UNC, 1/2-13-UNC, 9/16-12-UNC, 5/8-11-UNC, 3/4-10-UNC, 7/8-9-UNC, 1-8-UNC, #0-80-UNF, #1-72-UNF, #2-64-UNF, #3-56-UNF, #4-48-UNF, #5-44-UNF, #6-40-UNF, #8-36-UNF, #10-32-UNF, #12-28-UNF, 1/4-28-UNF, 5/16-24-UNF, 3/8-24-UNF, 7/16-20-UNF, 1/2-20-UNF, 9/16-18-UNF, 5/8-18-UNF, 3/4-16-UNF, 7/8-14-UNF, 1-12-UNF Custom Thread Units
mm, in Major Diameter
x >= 0Pitch (mm) or TPI
x >= 0Thread Engagement (%)
50 <= x <= 100Available Drills
auto, metric, imperial Response
Tool output
Output-contract version for this tool. Currently "1" for all tools.
Credits this call consumed, after any settlement refund. 0 when metering is disabled.
Credits left in the current monthly allowance, or null when metering is disabled.