An online calculator to calculate the current passing through a resistor using Ohm's law and the power dissipated in a resistor given the voltage across the resistor.
This calculator also calculates the voltage and current through a resistor given the power dissipated by this resistor.

Ohm's law expresses the relationship between the current I passing through a resistor and the voltage V across that resistor of resistsnce R as follows:

V = R I , I = V / R or R = V / I

The rate at which heat is dissipated in a resistor is called power P and is given in terms of current I and voltage V by:

P = V I

Using Ohm's law above, we can rewrite the power P as

P = R I ^{ 2} , P = V ^{ 2} / R

## 1 - Ohm's law and Power Calculator Given Voltage and Resistance

Enter the resistance in Ohms and the voltage in volts as positive real numbers and press "Calculate Current and Power".

## 2 - Ohm's law and Power Calculator Given Power and Resistance

Enter the power in Watts and the resistance in Ohms and press "Calculate Voltage and Current".

## More References and Links

Ohm's law with ExamplesFree SAT II Physics Practice Solutions on DC Electric Circuits

Ohm's law