Battery Equivalents and Replacements

Volts and Amps to Watts Calculator

Here is simple volts and amps to watts calculator, with short explanations, formulas, and charts.

Unit conversions sometimes can be difficult, but with most basic electric units like the voltage, current, and power, things are almost always very simple. Almost always...

Updated: August 13, 2022.

volts amps to watts calc 1

How to Convert Volts and Amps to Watts and Other Formulas

In order to convert volts, amps, and watts, we need to use these formulas:

  • P (W) = I (A) * U (V)
  • I (A) = P (W) / U (V)
  • U (V) = P (W) / I (A)

Note: these formulas are for either DC (Direct Current) electric systems or for AC (Alternate Current) electric systems using 'effective' values and α=0° (α is the phase angle between voltage and current).

Amps and Volts to Watts and Other Conversion Calculators

In order to convert volts, amps, and watts, feel free to use these conversion calculators - write the values that You have and click 'Calculate' to convert them:

Amps and Volts to Watts




Watts and Volts to Amps




Watts and Amps to Volts




2000 Watts to Amps and Volts

If You plan on having a 2000 Watts load (power generator, power inverter, UPS device, etc.), it is recommended to know the required current (A or Amps) and voltage (V) - the higher the voltage, the less current is required, leading to thinner cables or less energy loses. However, higher voltages can be harmful. The following chart lists required Amps and Voltages for the required 2000 watts of power.

Voltage (V) 12V 24V 36V 48V 120V 230V
 Current (A) 166.6A 83.3A 55.5A 41.6A 16.66A 8.695A

 As one can see, if the nominal voltage is increased from 12V to 48V, the current is decreased 4x, leading to a rather acceptable current of 41.66 Amps (from 166.6A!).

3000 Watts to Amps and Volts

Similarly, if the load is 3000W or even larger, higher voltages are required in order to keep the current at acceptable levels:

Voltage (V) 12V 24V 36V 48V 120V 230V
 Current (A) 250A 125A 83.3A 62.5 25A 13.04A

In order to find out exact voltages, currents and wattages, feel free to use our conversion calculators.

Watts, Volts, and Amps Conversion Frequently Asked Questions (FAQ)

Here are the most common Frequently Asked Questions (FAQ) about electric unit (Volts, Amperes, Watts) conversions:

How to calculate Amps from Watts and Volts?

To calculate the current in the electric circuit from Watts and Volts, use the following formula:

I(A) = P(W) / U(V)

How to calculate Watts from Volts and Amps?

To calculate the power in the electric circuit from Amps and Volts, use the following formula:

P(W) = I(A) x U(V)

How to calculate Volts from Watts and Amps?

To calculate the voltage in the electric circuit from Watts and Amps, use the following formula:

U(V) =P(W) / I(A)

How many Watts are 240 Volts?

If we know the voltage of the electric circuit, to calculate the circuit's power, we must find out the electric current (A) in the electric circuit.

For example, if the current is 3 Amp, the circuit power is:

P(W) = I(A) * U(V) = 3 Amp * 240V = 720 Watts

How many Volts are 100 Watts?

Similarly, to find out the voltage of the circuit, we need the circuit's current - for example, if the circuit current is 5 Amp, the circuit voltage is:

U(V) = P(W) / I(A) = 100W / 5A = 20V

How many Amps are 1000 Watts at 240 Volts?

If the circuit features a voltage of 240V and transfers 1000 Watts, then the current is:

I(A) = P(W) / U(V) = 1000 Watts / 240V = 4.166 Amps

How many Watts is a 120V bulb?

Incandescent 120V bulbs are usually between 60-120W, while LED bulbs are 7-18W.

What does the 120V 60Hz mean?

That means that there is 120V between the phase and neutral wire, and the AC current frequency is 60 Hz.

Long Story Short: If You want to convert amps and volts to watts, simply multiply the amps and volts. In order to get amps from watts and volts, divide watts with volts, and in order to get volts from watts and amps, divide watts with amps.

And all these formulas are good for DC electric systems and for AC electric systems where α=0° (cos 0°=1) and effective values are used.