CNC Feeds and Speeds Calculator
Calculate spindle RPM and feed rate for milling or routing from values you provide. Results are starting parameters; verify them with the tool manufacturer and your machine records.
Cutting inputs
Calculated starting values
- Spindle speed
- 7,958 RPM
- Feed rate
- 795.77 mm/min
- Surface speed
- 150 m/min
- Chip load
- 0.05 mm/tooth
- Plunge rate input
- 50 mm/min
- Depth of cut input
- 3 mm
- Stepover input
- 3 mm
Formulas
- RPM = (surface speed × 1000) ÷ (π × tool diameter) when metric inputs are used.
- Feed rate = RPM × flute count × chip load.
- The displayed RPM is capped at the entered spindle limit.
Assumptions
- Results are starting parameters, not production settings.
- Confirm chip load, surface speed, plunge, depth, and stepover with the tool manufacturer and machine records.
- The model does not infer material, tool geometry, rigidity, coolant, or machine-specific limits.
Feed and speed calculation
This CNC feed rate calculator uses the entered surface speed, tool diameter, flute count, and chip load to calculate RPM and feed rate.
Metric RPM = (surface speed in m/min × 1000) ÷ (π × tool diameter in mm). Feed rate = RPM × flute count × chip load. Imperial inputs are converted to metric for the calculation and returned in the selected units.
The result does not account for material-specific cutting data, tool geometry, stickout, rigidity, coolant, engagement, or machine condition.