Amps to Watts Calculator
Convert amperes to watts for any voltage. Enter the current in amps and voltage to calculate power in watts. Works for 120V, 240V, and three-phase systems.
How to Convert Amps to Watts
The formula to convert amps to watts is: Watts = Amps × Volts. This comes directly from Ohm's Lawand the power equation P = V × I, where P is power in watts, V is voltage in volts, and I is current in amperes.
Single-phase: W = A × V
Three-phase: W = A × V × √3 (1.732)
For example, a 20-amp circuit at 120 volts delivers 2,400 watts (20 × 120). The same 20 amps at 240 volts delivers 4,800 watts — which is why high-power appliances like dryers and ovens use 240V circuits.
Amps to Watts Conversion Chart
| Amps | @ 12V (DC) | @ 120V | @ 240V | @ 480V (3Φ) |
|---|---|---|---|---|
| 1 A | 12 W | 120 W | 240 W | 831 W |
| 2 A | 24 W | 240 W | 480 W | 1,663 W |
| 5 A | 60 W | 600 W | 1,200 W | 4,157 W |
| 10 A | 120 W | 1,200 W | 2,400 W | 8,314 W |
| 15 A | 180 W | 1,800 W | 3,600 W | 12,470 W |
| 20 A | 240 W | 2,400 W | 4,800 W | 16,627 W |
| 30 A | 360 W | 3,600 W | 7,200 W | 24,941 W |
| 40 A | 480 W | 4,800 W | 9,600 W | 33,254 W |
| 50 A | 600 W | 6,000 W | 12,000 W | 41,568 W |
| 60 A | 720 W | 7,200 W | 14,400 W | 49,882 W |
| 80 A | 960 W | 9,600 W | 19,200 W | 66,509 W |
| 100 A | 1,200 W | 12,000 W | 24,000 W | 83,136 W |
| 200 A | 2,400 W | 24,000 W | 48,000 W | 166,272 W |
Frequently Asked Questions
How do you convert amps to watts?
Multiply amps by volts to get watts. The formula is: Watts = Amps × Volts. For example, 15 amps at 120 volts equals 1,800 watts (15 × 120 = 1,800). For three-phase circuits, multiply by √3 (1.732): Watts = Amps × Volts × 1.732.
How many watts is 20 amps at 120V?
20 amps at 120 volts equals 2,400 watts (20 × 120 = 2,400). This is the maximum wattage for a standard 20-amp household circuit. However, NEC requires you to load circuits to only 80% for continuous loads, so plan for 1,920 watts maximum continuous.
How many watts is 15 amps?
It depends on the voltage. At 120V, 15 amps = 1,800 watts. At 240V, 15 amps = 3,600 watts. At 12V (automotive), 15 amps = 180 watts. You always need to know the voltage to convert amps to watts.
How many watts is 30 amps at 240V?
30 amps at 240 volts equals 7,200 watts (30 × 240 = 7,200). This is the capacity of a typical 30-amp dryer or EV charger circuit.
What is the difference between amps and watts?
Amps measure the flow of electrical current (how many electrons pass a point per second). Watts measure power (the rate of energy use). Think of it like water: amps are the flow rate, voltage is the pressure, and watts are the total work being done. You need both amps and voltage to calculate watts.
How many watts can a 15-amp breaker handle?
A 15-amp breaker at 120V can handle 1,800 watts maximum. But for continuous loads (running more than 3 hours), the NEC 80% rule limits you to 1,440 watts. This is why most kitchen circuits are 20-amp.
How many watts is 50 amps at 240V?
50 amps at 240 volts equals 12,000 watts (50 × 240 = 12,000). This is the capacity of a typical electric range circuit or a large EV charger (Level 2).
Related Electrical Calculators
Watts to Amps Calculator
Reverse conversion — convert watts to amps for breaker and wire sizing.
Convert Watts to Amps →Volts to Watts Calculator
Convert voltage and current to power for any electrical circuit.
Convert Volts to Watts →Ohm's Law Calculator
Calculate voltage, current, resistance, and power using all 12 Ohm's Law formulas.
Calculate Ohm's Law →Wire Sizing Calculator
Once you know the amps, find the correct wire gauge per NEC ampacity tables.
Calculate Wire Size →Breaker Size Calculator
Determine the right breaker size based on your circuit's amperage and load type.
Calculate Breaker Size →kW to Amps Calculator
Convert kilowatts to amps for single-phase and three-phase circuits.
Convert kW to Amps →