End mill speed and feed calculator converts cutter diameter, target surface speed, flute count, and chip load into spindle RPM and table feed rate for milling.
Get RPM and feed rate for an end mill in one step from diameter, target SFM, flute count, and chip load.
RPM = (SFM x 3.82) / D. Feed = RPM x Chip Load x Flutes. Treat as a starting point and adjust for rigidity, overhang, and finish requirements.
How it works
This combines the two most common shop-floor lookups, spindle speed from surface speed, and feed rate from chip load, into a single pass so an end mill setup is one calculation instead of two.
FAQ
Why does my feed look low? Small-diameter, high-flute-count end mills often need feed rates that surprise people; trust the chip load number over intuition.
Related Guides
How it works
This combines the two core milling calculations, RPM from SFM and diameter, then feed rate from RPM, chip load, and flute count, into one starting point for a new job. Treat the result as a starting point, not a fixed answer: rigidity, tool overhang, depth of cut, and desired finish all justify adjusting up or down from the calculated value.
FAQ
Should I use the full flute count in the feed calculation? Only for flutes actually engaged in the cut. On tools with more flutes than fit the radial depth of cut, or in slotting where chip clearance is limited, the effective flute count used for feed calculations is sometimes lower than the tool’s total flute count.
Related Guides
CNC Calculators · Face Mill Speed and Feed Calculator · Chip Load Calculator