Electricity Cost Calculator
Cost to run appliances.
Open →
Energy
Amps to Watts Calculator
Convert amps to watts from the voltage and power factor.
1 for resistive/DC
Power
—
Watts.
| Watts | — |
|---|---|
| Kilowatts | — |
| Voltage | — |
| Formula | — |
Show our math
Enter your figures above to see the step-by-step working.
Everything computed client-sideEverything computed client-side — nothing leaves this page
How the Amps to Watts Calculator Works
Watts are volts times amps: multiply the current by the voltage (and the power factor for AC) to get power. This tells you how much a device actually draws — useful for checking that a circuit, generator or power supply can handle the total load. A 15 A load on a 120 V circuit is 1,800 watts.
For DC and resistive AC loads, power factor is 1. For motors and many electronics it’s lower, which slightly reduces the real power for the same current.
watts = amps × volts × power factor
Frequently Asked Questions
How do I convert amps to watts?
Multiply the amps by the voltage (and power factor for AC). 15 amps at 120 volts is 1,800 watts.
How many watts is 20 amps at 120 volts?
2,400 watts (20 × 120). At 240 volts it would be 4,800 watts.
Does this work for a generator?
Yes. Multiply the generator’s amp rating by its voltage to see the wattage it can supply.
More From The Desk
Same plain method, different figuresWatts to Amps Calculator
Watts to current.
Open →Watts to kWh Calculator
Watts to energy used.
Open →Solar Panel Calculator
Solar system sizing.
Open →