Machining / interactive calculator

Material Removal Rate & Spindle Power Calculator

Estimate milling removal rate, cutting power, required spindle power, and torque from engagement, feed, specific cutting energy, and drivetrain efficiency.

01 / Cutting inputs

Live calculation

Radial width of cut

Engaged cutter width (a_e).

Axial depth of cut

Engaged axial depth (a_p).

Table feed

mm/min

Programmed cutting feed, excluding rapids.

Specific cutting energy

J/mm3

Enter a value supported by tooling or process data.

Drivetrain efficiency

Estimated power available at the cutting edge.

Spindle speed

RPM

Used with net cutting power to estimate cutting torque at the spindle.

Formula & assumptions

How removal rate and power are estimated

Material removal rate

MRR = ae x ap x table feed

With millimetre inputs this produces mm3/min; divide by 1,000 for cm3/min.

Power and torque

Cut torque = cut power x 30,000 / (pi x RPM)

Required spindle power adds the entered drivetrain-loss allowance. Cutting torque follows the cited Sandvik convention and uses net cutting power, not the loss-adjusted drive power.

Production application disclaimerThis is a planning estimate, not a machine-load guarantee. Specific cutting energy changes with material, hardness, chip thickness, tool geometry, wear, coolant, and cutting conditions. Check the machine power/torque curve and tooling guidance.

Follow the units from removed volume to power

With radial engagement a_e and axial depth a_p in mm and table feed v_f in mm/min, volume rate Q = a_ea_pv_f is mm³/min. For specific cutting energy u in J/mm³, cutting power in kW is P_cut = Q × u / 60,000: divide by 60 for seconds and by 1000 for watts to kilowatts. Required drive power is P_cut/η, where η is efficiency expressed as a decimal.

Illustrative milling inputs: a_e = 2 mm, a_p = 5 mm, feed = 800 mm/min, u = 2.5 J/mm³, efficiency = 85%, spindle = 5000 RPM
Quantity	Expected value
MRR	8000 mm³/min = 8 cm³/min
Net cutting power	8000 × 2.5 / 60,000 = 0.333333 kW
Loss-adjusted drive power	0.333333 / 0.85 = 0.392157 kW
Cutting torque	0.333333 × 30,000 / (π × 5000) = 0.636620 N·m

The energy input is not a generic material guarantee

The example’s 2.5 J/mm³ is hypothetical. Changing it to 3.0 while holding geometry fixed increases both calculated powers and cutting torque by 20%. Obtain an applicable value from documented tooling/process data and record its material and cutting-condition basis. Do not paste an N/mm² cutting-force coefficient into a J/mm³ field without understanding the model and unit conversion.

Compare the relevant power and torque against the machine’s curves at the actual RPM, not only its maximum nameplate power. Read MRR and power and torque. Reference: Sandvik net-power and torque definitions.