Feed Rate Calculator Formula

Understand the math behind the feed rate calculator. Each variable explained with a worked example.

Formulas Used

Table Feed Rate (Vf)

feed_rate = feed_per_tooth * num_teeth * spindle_rpm

Feed per Revolution

feed_per_rev = feed_per_tooth * num_teeth

Variables

VariableDescriptionDefault
feed_per_toothFeed per Tooth (fz)(mm/tooth)0.1
num_teethNumber of Cutter Teeth (z)4
spindle_rpmSpindle Speed (N)(RPM)1000

How It Works

Milling Feed Rate Calculation

The table feed rate determines how fast the workpiece moves past the cutter.

Formula

Vf = fz x z x N

where fz is the feed per tooth (chip load), z is the number of cutting teeth on the milling cutter, and N is the spindle speed in RPM. The result is the linear table feed rate in mm/min.

Worked Example

A 4-flute end mill at 1000 RPM with 0.1 mm/tooth feed.

feed_per_tooth = 0.1num_teeth = 4spindle_rpm = 1000
  1. 01Feed per revolution = 0.1 x 4 = 0.4 mm/rev
  2. 02Table feed = 0.1 x 4 x 1000 = 400 mm/min

Ready to run the numbers?

Open Feed Rate Calculator