Metric spindle speed
RPM = (vc × 1000) ÷ (π × D)vc is cutting speed in metres per minute. D is cutter diameter in millimetres.
Machining / interactive calculator
Milling Speeds & Feeds Calculator
Calculate spindle speed and feed rate from cutting speed, cutter diameter, flute count, and chip load. Switch units without losing the current values.
m/min
Use a value appropriate to the tool and material.
mm
Use effective cutting diameter where applicable.
z
Number of cutting edges engaged per revolution.
mm/tooth
Programmed feed per tooth, before special corrections.
Formula & assumptions
How the result is calculated
Imperial spindle speed
RPM = (SFM × 12) ÷ (π × D)SFM is surface feet per minute. D is cutter diameter in inches.
Table feed
Feed = RPM × z × fzz is the number of flutes or teeth. fz is programmed chip load per tooth.
What this tool does not select
Tooling data + material + setup → starting inputsThe calculator evaluates the inputs you provide. It does not choose a safe cutting speed or chip load for a specific tool, material, machine, or setup.
Production application disclaimerEducational starting point only. Verify cutting speed and chip load against current tooling data, then check spindle limits, workholding, tool stickout, coolant, machine condition, and material before production. Reduce or adjust values when the setup requires it.