Milling Speeds and Feeds Calculator
Find a safe starting RPM and feed rate for an end mill. Enter the cutter diameter, number of flutes and surface speed, then fine tune the chip load to match your machine and workholding.
Milling speeds and feeds
Power is a rough estimate using the material unit power factor. Verify against your spindle rating.
Spindle speed
- RPM
Feed rate
- IPM
Material removal rate
- in3/min
Approx. spindle power
- HP
Editorial estimate only
These are conservative starting points, not a guarantee. Verify against manufacturer tooling data and your machine manual. Confirm spindle power, workholding and coolant before cutting.
Milling formulas
RPM = (SFM x 12) / (pi x cutter diameter in inches)
Feed rate = RPM x chip load per tooth x number of flutes
Material removal rate = feed rate x width of cut x depth of cut
Getting a good result
Start on the low end of the surface speed range and keep chip load conservative. Reduce chip load for small cutters and long stickout. Verify the spindle has enough power and that the part is held rigidly.