CNC Power Requirement Calculator 2026
Calculate spindle power needed for your machining operations. Verify motor capacity, estimate current draw, and optimize cutting parameters for 17+ material types.
Power Calculator
Enter material and cutting parameters to calculate power requirements
Power Formula
P = (MRR × Kc) / 60,000P = Power (kW)
MRR = Material Removal Rate (mm³/min)
Kc = Specific cutting force (N/mm²)
💡 Kc Values
Understanding Power Requirements
Why Power Calculation Matters
Knowing power requirements before machining prevents spindle overloads, motor damage, and production interruptions. Under-powered cuts result in poor surface finish and tool damage. Over-capacity wastes energy and machine potential.
Net vs. Gross Power
Net power is consumed at the cutting edge - the actual work done removing material. Gross power is what the motor must provide, accounting for drive train losses. A belt-driven spindle might be 70% efficient, meaning 10 kW at the cutter requires 14.3 kW at the motor.
Spindle Utilization Guidelines
Optimal (50-80%)
Best balance of productivity and machine longevity. Leaves headroom for tool wear, interrupted cuts.
Danger (95%+)
Risk of thermal protection trips, bearing damage, motor burnout. Reduce MRR immediately.
Power Optimization Tip
If power is limiting your productivity, consider: higher radial depth with lower axial depth (uses more flutes), higher feed rate with shallower cuts, or material-specific strategies like high-speed machining for aluminum.
Related Calculators
Frequently Asked Questions
Power (kW) = MRR (mm³/min) × Kc (N/mm²) / 60,000. MRR is Material Removal Rate (axial depth × radial depth × feed rate). Kc is the specific cutting force for your material. This gives net power at the cutting edge; divide by machine efficiency (70-85%) for gross motor power.