Volts to Watts Calculator

Q: How do I convert volts to watts?

Multiply voltage by current: W = V × A. For AC single-phase, also multiply by the power factor: W = V × A × PF. For three-phase: W = √3 × V × A × PF. You must know the current — voltage alone is not enough.

Q: Can I convert volts to watts without amps?

No. Watts is the product of volts and amps, so you must know the current. If you know resistance instead, first find current with Ohm's Law (A = V ÷ R), then use W = V × A.

Q: How many watts is 120 volts?

It depends on the current. At 120 V drawing 1 A that is 120 W; at 5 A it is 600 W; at 12.5 A it is 1,500 W. Multiply 120 by the amps the device draws.

Q: What is the difference between volts and watts?

Volts measure electrical pressure (potential difference); watts measure power (the rate energy is used). Watts equal volts times amps, so a high voltage at low current can deliver the same watts as a low voltage at high current.

Reviewed by the ElectricalConverters editorial team Last updated July 2026 Estimates only — how we check

Enter voltage and current below — the watts update instantly.

Voltage (V)

Current (A)

Circuit Type

RESULT — POWER

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Choose a circuit type and enter values to see the formula used.

How do you convert volts to watts?

Multiply volts by amps: W = V × A. A device at 120 V drawing 5 A uses 120 × 5 = 600 W. Voltage alone cannot give watts — you need the current too. For AC single-phase, include the power factor: W = V × A × PF, so 120 V at 5 A with PF 0.9 gives 120 × 5 × 0.9 = 540 W.

Volts to Watts Formula

DC Circuits

W = V × A

Power is simply voltage times current. Example: a 12 V circuit carrying 2 A delivers 12 × 2 = 24 W.

AC Single-phase

W = V × A × PF

Real power on AC is scaled by the power factor. A resistive heater sits near PF 1.0; motors and switch-mode supplies run lower.

AC Three-phase

W = √3 × V × A × PF

The √3 factor (≈ 1.732) applies to balanced three-phase loads. Use the line-to-line voltage (e.g. 400 V or 480 V).

Common Volts to Watts Values (DC / PF 1.0)

Voltage	at 1 A	at 5 A	at 10 A	at 20 A
12 V	12 W	60 W	120 W	240 W
24 V	24 W	120 W	240 W	480 W
120 V	120 W	600 W	1,200 W	2,400 W
230 V	230 W	1,150 W	2,300 W	4,600 W
240 V	240 W	1,200 W	2,400 W	4,800 W

Frequently Asked Questions

How do I convert volts to watts?

Multiply voltage by current: W = V × A. For AC single-phase: W = V × A × PF. For three-phase: W = √3 × V × A × PF. You need the current as well — voltage on its own cannot give watts.

Can I convert volts to watts without amps?

No — watts is volts times amps, so the current is required. If you only know resistance, first find current with Ohm's Law (A = V ÷ R), then apply W = V × A.

How many watts is 120 volts?

It depends on the current the device draws. At 120 V: 1 A = 120 W, 5 A = 600 W, 12.5 A = 1,500 W. Enter the current above for an exact figure.

What is the difference between volts and watts?

Volts measure electrical pressure; watts measure power. Since W = V × A, a high voltage at low current can deliver the same wattage as a low voltage at high current. See watts vs amps for more.