Voltage from Current and Power

The Voltage from Current and Power calculator computes the Voltage (V) based on Ohm's Law using Power (P) and Current (I).

INSTRUCTIONS: Choose units and enter the following:

• (P) Power
• (I) Current

Voltage (V): The calculator returns the potential in volts.  However, this can be automatically converted to other electric potential units via the pull-down menu.

General Information

 For more information on the relationship between electrical power, current, resistance and potential, see the Ohm's Law Calculator.

Ohm's Law

The Ohm's Law calculator suite computes power (watts), potential (voltage), current (amps) and resistance (ohms) in relation to each other based on Ohm's Law.  There is a fundamental relationship between electrical parameters: potential, current, resistance and power depicted in the graphical wheel (see wheel).  

The Ohm's Law Calculator suite has automatic unit conversions for the input and output of the equations.  The equations are as follows.  Click on the formula for a pop-up calculator with the formula, or click on the description link for the page dedicated to that formula.

Power (watts, milliwatts, kilowatts)

• Power (P) = I • V :  Computes the power (watts) as a function of current (amps) and potential (volts).
• Power (P) = R • I² : Computes the power (watts) as a function of current (amps) and resistance (ohms).
• Power (P) = V² / R: Computes the power (watts) as a function of potential (volts) and resistance (ohms).

Potential (volts, millivolts)

• Volts (V) = I • R  : Computes the potential (volts) as a function of current (amps) and resistance (ohms).
• Volts (V) = P / I  : Computes the potential (volts) as a function of power (watts) and current (amps).
• Volts(V) = √(P • R) : Computes the potential (volts) as a function of power (watts) and resistance (ohms).

Resistance (ohms, milliohms, kiloohms)

• Resistance (R) = V²/P : Computes the resistance (ohms) as a function of potential (volts) and power (watts).
• Resistance (R) = P / I²  : Computes the resistance (ohms) as a function of power (watts) and current (amps).
• Resistance (R) = V / I  : Computes the resistance (ohms) as a function of potential (volts) and current (amps).

Current (amps, milliamps, microamps, gilberts)

• Current (I) = V / R : Computes the current (amps) as a function of potential (volts) and resistance (ohms).
• Current (I) = P / V  : Computes the current (amps) as a function of the power (watts) and the potential (volts).
• Current (I) = √(P/R) : Computes the current (amps) as a function of the power (watts) and the resistance (ohms).