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Ohm's Law & Watt's Law Calculator
Enter any two known values and press Calculate below to solve for the remaining values.

Press reset after each calculation
Electrical Properties
  • Electromotive Potential

    Measured in Volts, is represented by the letter V (or E)

  • Current

    Measured in Amperes, is represented with the letter I

  • Resistance

    Measured in Ohms, is represented by the letter R (or the Greek letter Ω)

  • Power

    Measured in watts, is represented by the letter W

Ohm's Law

States the relationship between voltage, current and resistance. Given the relationship between these three elements, once you know any two of them, it is possible to calculate the third.

  • V = IR
    Volts = Amps x Ohms
  • I = V/R
    Amps = Volts / Ohms
  • R = V/I
    Ohms = Volts / Amps
Watt's Law

Watt's Law is similarly useful in figuring out the relationship between power, voltage and current.

  • W = VI
    Watts = Volts x Amps
  • V = W/I
    Volts = Watts / Amps
  • A = W/V
    Amps = Watts / Volts
Ohm's Law Pie Chart