volts to watts

Watts are what you pay for — volts times amps, nothing more. A 120 V bulb drawing 0.5 A burns 60 W, and a 120 V heater pulling 15 A burns 1,800 W. This calculator applies P = V·I, the watt's law companion to Ohm's law, and it is the conversion behind every appliance label, breaker load calculation, and electricity bill in the world.

By EnginStack Engineering Team | Verified by engineers, built on NIST metrology standards About →
volts
amps
— watts
— —

Source: NIST SP 811 and the 1959 yard-and-pound agreement (0.9144 m, 0.45359237 kg). Every decimal place in the factor above is a defined constant, not a measurement.

volts to watts

Power in watts is the rate of energy use, and P = V·I is exact for DC and for resistive AC loads (which covers heaters, bulbs, and most household appliances; motors and reactive loads carry an additional power factor). The US 120 V / 240 V split means the same 15 A delivers 1,800 W at 120 V but 3,600 W at 240 V — which is exactly why ranges and dryers run on 240 V. Every load calculation that sizes a circuit sums watts first, then converts to amps at the circuit voltage.

watts = volts × amps
P = V·I
Exact watt's law — the product of the voltage and current you provide.

Common volts to watts Values

voltsampswattsContext
120 V0.5 A60 WIncandescent bulb.
120 V5 A600 WMicrowave oven.
120 V15 A1,800 WSpace heater at full load.
240 V15 A3,600 WElectric dryer.
12 V10 A120 WAutomotive accessory.

Engineering Context

Volts-to-watts is the bridge between the electric hub and the energy family — watts are the electric unit that connects to watts to kW and kWh billing via Wh to kWh. The reverse conversion lives on watts to volts, and the current side on watts to amps.

More: W to V · W to A · W to kW · Electric Hub

Related Unit Converters

Watts To Volts Watts To Amps Watts To Kw Electric Converters

Frequently Asked Questions

How do I convert volts to watts?

Multiply volts by amps: P = V·I. A 120 V device drawing 0.5 A consumes 60 W. If you know resistance instead, P = V²/R gives the same answer.

Why do dryers and ranges use 240 volts?

Because power scales with voltage: P = V·I. The same 15 A breaker delivers 1,800 W at 120 V but 3,600 W at 240 V — double the heating capacity from the same wire size and breaker.

Is volts times amps always watts?

For DC and resistive AC loads (heaters, bulbs), yes — exactly. For motors and other reactive loads, the real power is V·I·power factor, and the power factor (usually 0.7–0.95) must be included.