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CNC Machining Calculators & Engineering Tools

103 free calculators and engineering references for CNC programmers, machinists, estimators, and manufacturing engineers.

Cutting Parameters

24 calculators — Speeds & feeds, chip load, SFM, MRR, cycle time, horsepower, cutting force, surface roughness, tool path geometry, and a cutting speed chart covering every ISO material group

Drilling, Tapping & Threads

17 calculators — Tap drill size, tapping feed rate, drill point length, thread pitch, NPT pipe thread, peck drilling, countersink, reaming, and gun drilling

Materials & Grades

21 tools — Hardness converter, metal weight & cost, machinability, carbide grades, stainless properties, titanium guide, aluminum alloys, and coating selector

Cost, Tolerances & Reference

41 tools — Cost per part, batch cost, CNC ROI, OEE, tool life economics, ISO fits, bolt circle, GD&T, G-code reference, unit converters, shop planning, and end mill size charts

About these CNC machining calculators

These 103 tools are built for practicing machinists, CNC programmers, manufacturing engineers, estimators, and shop owners. Every calculator uses engineering-standard formulas from ISO, ASME, and industry references — the same math behind Sandvik Coromant ToolGuide, Kennametal NOVO, and Machinist's Handbook tables.

Frequently asked questions

Are these calculators free to use?

Yes, all 103 calculators and reference tools are completely free. No registration, no paywall, no trial period. Bookmark the ones you use most.

How accurate are the results?

All calculators use standard engineering formulas from ISO, ASME, and industry references. Results are accurate for theoretical calculations. Real-world results vary with machine rigidity, tool condition, coolant, and material batch variation — always verify with a test cut.

Can I use these calculators offline?

This is a web-based tool collection. You can save individual calculator pages for offline use in most browsers (Ctrl+S / Cmd+S). For shop-floor use, we recommend bookmarking on your phone or tablet.

Do you accept suggestions for new calculators?

Yes. If you need a specific CNC calculator that is not here, contact us with the formula or use case. We add new tools regularly based on user requests.