Planning estimates
CNC Feeds & Speeds Calculator
Estimate RPM and feed from surface speed, diameter, flute count and chip load. Always confirm toolmaker data and machine limits.
Formula reference
Approximate RPM for inch units: RPM = SFM × 3.82 ÷ diameter. Feed in inches per minute: feed = RPM × effective teeth × chip load.
Not a cutting prescription
Holder, stickout, runout, machine rigidity, toolpath engagement, coolant, material condition and workholding can require substantial adjustment.