CNC Chip Load Calculator
Chip load, the amount each cutting edge removes per revolution, is the key to a clean cut and long tool life. This calculator computes the chip load from your spindle speed, flute count and feed rate, and also solves for the feed rate from a target chip load taken from your tool data sheet. Enter feed rate and chip load in the same length unit (millimetres or inches) and the outputs stay consistent.
Chip load formula
Chip load = feed rate / (RPM * flutes)
Feed rate = chip load * RPM * flutes
The two forms are rearrangements of the same relationship. Keep feed rate and chip load in the same length unit so the result is consistent.
Worked example
At 18,000 RPM, 2 flutes, 2,160 mm/min feed: chip load = 2,160 / (18,000 * 2) = 2,160 / 36,000 = 0.06 mm/tooth. For a 0.06 mm/tooth target: feed rate = 0.06 * 18,000 * 2 = 2,160.00 mm/min.
CNC chip load: frequently asked questions
What is chip load?
Chip load, or feed per tooth, is the thickness of material each cutting edge removes per revolution. It equals the feed rate divided by the product of spindle speed and the number of flutes: chip load = feed rate / (RPM times flutes). Correct chip load protects the tool and gives a clean cut.
How do I find the feed rate for a target chip load?
Rearrange the formula: feed rate = chip load times RPM times the number of flutes. Enter the chip load recommended for your tool and material, and the calculator returns the feed rate to program.
What chip load should I use?
Recommended chip load depends on the cutter diameter, material and tool manufacturer, so this calculator does not supply one: you enter the value from the tool data sheet. Too low a chip load causes rubbing and heat; too high overloads the cutter.
Official sources
- U.S. National Institute of Standards and Technology: Intelligent Systems Division (machining and manufacturing metrology).
- The chip-load relationship follows from feed rate being the distance advanced per minute divided by the cuts made per minute.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.