Ohms Law Calculator

The three calculators below calculate voltage, current or resistance using ohms law. Fill in the two boxes on the left and the missing vlaue will be calculated and shown on the right. The resistance calculator also shows preferred resistor values; use the radio buttons on the calculator to select the preferred value series to use.

Voltage Calculator (V = I * R):

Enter Current:        Amps Milliamps Microamps		Voltage = ?
Enter Resistance:        Ohms Kilohms Megohms

Current Calculator (I = V / R):

Enter Voltage:        Volts Millivolts Microvolts		Current = ?
Enter Resistance:        Ohms Kilohms Megohms

Resistance Calculator (R = V / I):

Enter Voltage:        Volts Millivolts Microvolts		Resistance = ? Preferred Resistance = ?
Enter Current:        Amps Milliamps Microamps
Select preferred series (optional): E12    E24    E48    E96    E192

Formulae:

The formula for Ohms Law is:

V = I * R, where V is voltage, I is current and R is resistance

This can be re-arranged to find current or resistance:

I = V / R
R = V / I

For more details of Ohms Law, and the 'Ohms Law triangle' (an easy way to remember and re-arrange the formaula) click here.