Calculate CNC

Calculate CNC is a fast, no-nonsense set of shop-floor calculators and reference charts for machinists, CNC programmers, and toolmakers. Every formula and chart is checked against published standards (ASME, ISO, ANSI, Machinery's Handbook), so you can trust the number — then verify before you cut.

Works fully offline. No account, no sign-up, no ads, no tracking.

THREADING
• UN thread 3-wire measurement and pitch-diameter limits (ASME B1.1, classes 1A/2A/3A)
• Metric M-profile 3-wire measurement and limits (ISO 965, 4g6g/6g/6h)
• Stub Acme external thread, class 2G (ASME B1.8)
• Tap drill by percentage of thread, with nearest standard drill
• Single-point threading infeed (29.5°/30° compound)

LATHE
• Taper: angle, taper per foot, tailstock offset
• Cut time, knurl tracking, parts per bar
• Insert decoder — type an ISO/ANSI designation (DNMG, CNMG, WNMG…) and see the insert drawn to scale
• Boring-bar tool clearance visualizer

MILLING & DRILLING
• Speeds and feeds: RPM and feed from SFM and chip load
• Bolt circle and bolt-line hole coordinates
• Drill point depth, countersink and center-drill depth, countersink for flat-head screws

CNC & GEOMETRY
• Chip thinning (HSM), G02/G03 arc centers (I/J)
• Triangle solver, fillet/radius, circle segment, polar ↔ rectangular
• True position with MMC bonus, sine bar, spur gear, dovetail measurement

SHOP MATH & CHARTS
• Unit converter, surface speed, surface finish, material weight, box packing
• Drill chart, inch and metric tap charts, NPT pipe taps
• Socket head cap screws, center drills, flat-head screws
• ISO fits & tolerances (ISO 286), G & M code reference, GD&T reference
• Scientific calculator

Many tools include a live diagram so you can see the setup, not just the number.

Calculate CNC is a reference aid — not a substitute for engineering standards, gages, or your own judgment. Always confirm critical dimensions against the controlling standard or a calibrated gage before machining.

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