Feed Rate Calculator

Chip load (the material removed per tooth per revolution) is a property of the cutting tool and the material being cut, published by tooling manufacturers as a recommended range. Feed rate in inches per minute, by contrast, depends on the specific RPM and flute count you're running, so it changes every time those settings change. Chip load stays constant across different spindle speeds, which is why manufacturers publish chip load rather than a fixed feed rate.

Yes -- with chip load and flute count held constant, feed rate scales directly and proportionally with RPM. This is intentional: if you speed up the spindle without also increasing the feed rate proportionally, each tooth removes LESS material per pass than the target chip load, which causes rubbing instead of cutting.

Within this calculator's formula, yes -- more flutes means more cutting edges pass through the material per revolution, so total material removal (and therefore feed rate) scales up with flute count at a fixed chip load and RPM. In real-world machining this holds mainly for high-flute-count finishing cutters; roughing cutters with fewer, larger flutes are chosen for better chip clearance in the material being cut, a tradeoff this calculator does not model.

Feed per revolution measures how much the tool advances during ONE spindle revolution -- Chip Load × Number of Flutes -- so RPM, which measures revolutions per minute, cancels out of that particular figure entirely. RPM only enters the calculation once you convert to a per-MINUTE rate, which is what the main Feed Rate (IPM) result does.