Resistance Calculator Formula

Understand the math behind the resistance calculator. Each variable explained with a worked example.

Formulas Used

Resistance

resistance = voltage / current

Variables

VariableDescriptionDefault
voltageVoltage(V)12
currentCurrent(A)0.5

How It Works

Resistance

Resistance measures how strongly a component opposes the flow of electric current.

Formula

R = V / I

Derived from Ohm's law. The unit is the ohm (Ω), named after Georg Ohm.

Worked Example

A 12 V battery drives 0.5 A through a resistor.

voltage = 12current = 0.5
  1. 01R = V / I
  2. 02R = 12 / 0.5
  3. 03R = 24 Ω

Ready to run the numbers?

Open Resistance Calculator