Ohm's Law Calculator Formula

Understand the math behind the ohm's law calculator. Each variable explained with a worked example.

Use the Ohm's Law Calculator

Formulas Used

Resistance

resistance_ohm = voltage_v / current_a

Power

power_w = voltage_v * current_a

Variables

VariableDescriptionDefault
voltage_vVoltage(V)12
current_aCurrent(A)0.5

How It Works

How Ohm's Law Works

Ohm's Law links voltage, current, and resistance.

Formula

V = I x R

Where:

  • V = Voltage in volts
  • I = Current in amperes
  • R = Resistance in ohms

    • Rearranging gives R = V / I and I = V / R. Power is P = V x I.

    Worked Example

    A 12 V battery drives 0.5 A through a resistor.

    voltage_v = 12current_a = 0.5
    1. 01Resistance R = V / I = 12 / 0.5 = 24 ohms
    2. 02Power P = V x I = 12 x 0.5 = 6 W

    Ready to run the numbers?

    Open Ohm's Law Calculator