Amps Watts Volts Converter — P = V × I (Free)

Amps to watts, watts to amps, volts to amps, and VA to amps

Operating Mode

Required Parameters

Current

Voltage

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Quick Answer

Watts = amps × volts. Amps = watts ÷ volts. You cannot convert volts to amps with voltage alone — you also need watts, VA, or resistance.

Documentation

Amps Watts Volts Converter

Convert amps to watts, watts to amps, volts to amps, and VA to amps. The relationship is P = V × I — voltage or current alone is never enough.

Quick start: Pick Amps to Watts, enter 10 A and 120 V → 1.2 kW. Switch to Volts to Amps for I = P / V, or VA to Amps for nameplate apparent power.

Need a page that matches the search phrase? Use the dedicated Amps to Watts Calculator or Volts to Amps Calculator.

Formulas

Convert	Formula	Example
Amps → watts	P = I × V	10 A × 120 V = 1,200 W
Watts → amps	I = P / V	1,500 W / 120 V = 12.5 A
Volts → amps (power)	I = P / V	same as watts → amps
VA → amps (1-phase)	I = S / V	5 kVA / 240 V = 20.8 A
VA → amps (3-phase)	I = S / (√3 × VL)	5 kVA / (1.732 × 208 V) = 13.9 A

You cannot convert volts to amps by themselves

Volts measure potential; amps measure current. Without watts, VA, or resistance, the conversion is undefined. For I = V / R use the Ohm's law calculator.

Related tools

Amps to Watts Calculator
Volts to Amps Calculator
Electrical Power Calculator — P = I²R and V²/R
Three-Phase Power Calculator
RMS Voltage Calculator

Design Notes

You cannot convert volts to amps with voltage alone — power or resistance must be known. P = V × I is real power for DC and for AC at power factor 1. VA is apparent power; on three-phase systems line current uses √3. For resistive DC loads you can also use I = V / R or P = I²R.

Common Mistakes

1
Trying to convert volts to amps without watts, VA, or resistance — the units are not interchangeable by themselves.
2
Using P = V × I on a three-phase feeder without the √3 factor. Three-phase real power is √3 × VL × IL × PF.
3
Treating VA as watts when the load power factor is not 1. Watts = VA × PF.

Engineering Handbox

1. P = I × V 2. P = 10 × 120 = 1200 W

Verification10 A at 120 V is 1.2 kW. Reverse: I = 1200 / 120 = 10 A.

Knowledge Base

How do I convert amps to watts?

Multiply current by voltage: P = I × V. Example: 10 A at 120 V = 1,200 W. If you know resistance instead of voltage, use P = I²R.

How do I convert watts to amps?

Divide power by voltage: I = P / V. Example: a 1,500 W heater on 120 V draws 12.5 A. Check the breaker and wire size against that current.

Can I convert volts to amps without watts?

No. Volts and amps measure different quantities. You need power (I = P / V), apparent power (I = S / V), or resistance (I = V / R). This converter uses power; the Ohm's law calculator uses resistance.

How do I convert VA to amps?

Single-phase: I = VA / V. Three-phase: I = VA / (√3 × VL). Example: 5 kVA at 240 V single-phase is 20.8 A. At 208 V three-phase, 5 kVA is 13.9 A.

Is this the same as Ohm's law?

It uses the same DC/resistive math (P = V × I) but the search task is unit conversion, not solving a circuit. Use the Ohm's law calculator when you have V and R, and the power calculator when you want I²R or V²/R laid out as a solver.

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