Enter all but one of the feed per tooth (fz), feed rate (vf), spindle speed (n), number of teeth on the cutter (z), and axial depth of cut (ap) into the calculator to determine the remaining variable. This calculator can also evaluate any of the variables given the others are known.

Feed Per Tooth Formula

The following formula is used to calculate the feed per tooth (fz) for a milling operation:

fz = (vf * n) / (z * ap)


  • fz is the feed per tooth
  • vf is the feed rate
  • n is the spindle speed
  • z is the number of teeth on the cutter
  • ap is the axial depth of cut

To calculate the feed per tooth, multiply the feed rate by the spindle speed, then divide the result by the product of the number of teeth on the cutter and the axial depth of cut.

What is a Feed Per Tooth?

Feed Per Tooth, often abbreviated as FPT or Ft, is a critical parameter in machining operations, particularly in milling. It refers to the distance that the mill or cutter travels along the workpiece for every single tooth pass. This measurement is typically given in inches or millimeters and is crucial in determining the speed and feed rate of the milling operation. The Feed Per Tooth is directly related to the surface finish of the workpiece, the tool life, and the rate of material removal. Too high a feed per tooth can result in tool breakage or poor surface finish, while too low a feed per tooth can lead to inefficient machining and excessive tool wear. Therefore, it is essential to calculate and set the correct Feed Per Tooth for each specific machining operation.