Free CNC and Machining Calculators
Free calculators for machinists and CNC'ers. They all run in your browser, with nothing to download and no signup, and most work in inch or metric units.
Speeds and Feeds
- Milling Speeds and Feeds Calculator: spindle speed, feed rate, metal removal rate, and chip thinning for end mills.
- Lathe Speeds and Feeds Calculator: RPM, feed rate, removal rate, and surface finish for turning with carbide inserts.
- CNC Router Feeds and Speeds Calculator: RPM and feed rate for router bits in hardwood, softwood, plywood, and MDF.
- Drilling Speeds and Feeds Calculator: RPM, feed rate, and drilling time for twist drills, with peck drilling tips.
- Tap Speed and Feed Calculator: tapping RPM and feed for UNC, UNF, and metric threads, with tap drills and a G84 line.
- Chip Load Calculator: chip load from your feed and speed, including radial chip thinning.
- SFM to RPM Calculator: convert surface speed to spindle RPM and back.
- Slitting Saw Calculator: speed, feed, passes, and teeth in the cut for slitting saws.
- Helical Interpolation and Ramp Angle Calculator: programmed feed, ramp angle, and plunge rate for helixing into a cut.
Threads and Holes
- NPT Thread Calculator: NPT pipe thread dimensions and tap drills.
- Countersink Depth Calculator: countersink depth from diameter, and diameter from depth.
- Bolt Circle Calculator: hole coordinates and G-code for bolt circles.
- Polar to Cartesian Calculator: convert between polar and X/Y coordinates.
Tolerances, Fits, and Materials
- True Position Calculator: GD&T true position with MMC and LMC bonus tolerance.
- Press Fit Calculator: ISO hole and shaft tolerances for press, sliding, and running fits.
- Hardness Conversion Calculator: convert between Rockwell, Vickers, Brinell, Shore, and tensile strength.
- Thermal Expansion Calculator: how much a part or bore grows with temperature, and shrink fit temperatures.
Shop and Materials
- Board Foot Calculator: board feet and cost for a list of lumber.
- Metal Weight Calculator: weight and cost of plate, bar, hex, pipe, and tubing in steel, aluminum, brass, and more.
- Steel Beam and Structural Shape Calculator: weight and cost of I-beams, channel, angle, and tubing.
- CNC Machine Hourly Rate Calculator: what a machine costs per hour to own and run, for quoting jobs.
Learn the Formulas
The Feeds and Speeds Guide explains how surface speed, chip load, and chip thinning work, and our Cutting Speed Formulas article shows the math behind these calculators.