Tool Power Calculator
Calculate electrical power requirements for woodworking tools and plan workshop circuits.
Tool Specifications
Power Requirements
Enter tool specifications to calculate power requirements.
How to Use This Calculator
- 1 Select Tool Type Choose from common woodworking tools (table saw, planer, jointer, etc.).
- 2 Motor HP Select the motor horsepower rating from the tool nameplate.
- 3 Voltage Choose 120V (standard) or 240V.
- 4 Phase Select single-phase (residential) or three-phase (commercial).
Watts = HP × 746 | Amps = Watts ÷ Volts | Motor HP | Watts | Amps @120V | Amps @240V | Recommended Circuit |
|---|---|---|---|---|
| 1/2 HP | 373W | 3.1A | 1.6A | 15A @120V |
| 3/4 HP | 560W | 4.7A | 2.3A | 15A @120V |
| 1 HP | 746W | 6.2A | 3.1A | 15A @120V |
| 1.5 HP | 1,119W | 9.3A | 4.7A | 15A @120V |
| 2 HP | 1,492W | 12.4A | 6.2A | 20A @120V or 15A @240V |
| 3 HP | 2,238W | 18.7A | 9.3A | 240V required (15A) |
| 5 HP | 3,730W | 31.1A | 15.5A | 240V required (20A) |
- Never Exceed 80%: Continuous loads should not exceed 80% of circuit capacity
- Proper Wire Gauge: Use correct wire gauge for the amperage and run length
- Dedicated Circuits: Each stationary tool should have its own dedicated circuit
- 240V for Large Tools: More efficient, halves amperage, reduces voltage drop
- Consult an Electrician: Always hire a licensed electrician for new circuits
Glossary of Terms
Unit of power. 1 HP = 746 watts. Motor nameplate HP indicates maximum continuous output power.
Electrical current draw. Higher amps require larger wire and circuit breakers. Amps = Watts ÷ Volts.
Momentary high current draw when a motor starts. Typically 2-6× the running amperage. Size circuits to handle surge without tripping breakers.
An electrical circuit serving only one tool or outlet. Required for stationary tools to prevent overloading shared circuits.
Frequently Asked Questions
When should I use 240V instead of 120V?
Use 240V for motors 2 HP and above. Benefits: halves the amperage (smaller wire gauge), reduces voltage drop on long runs, and provides more consistent power delivery for large motors.
How do I size wire for my workshop tools?
Wire gauge depends on amperage and distance. For typical workshop runs (under 50 feet): 15A circuits use 14 AWG, 20A use 12 AWG, 30A use 10 AWG. Longer runs may require upsizing.
Can I run multiple tools on one circuit?
Not recommended for stationary tools. Each should have a dedicated circuit. Portable tools (sanders, drills) can share circuits if combined load doesn't exceed 80% of capacity.
What is a three-phase motor?
Three-phase power is commercial/industrial power using three alternating currents. More efficient for large motors but requires special wiring not available in most residential setups. Phase converters can generate 3-phase from single-phase.