Parallel Resistor Calculator

Build a parallel circuit, calculate equivalent resistance, and visualize branch currents automatically.

Circuit Setup
Power Source 12 V
Resistors (Parallel)
Equivalent Resistance (Rₜ)
0 Ω
Total Current (Iₜ)
0 A

Parallel Law: Notice that adding more resistors in parallel actually decreases your total resistance, because you are creating more paths for the electricity to flow!

How Parallel Circuits Work

A "parallel" circuit means the electrical components are connected across the same two points, creating multiple separate branches for the electricity to flow through.

  • Total Resistance Decreases: Unlike series circuits, adding more resistors in parallel gives the current more paths to take. The total (equivalent) resistance is always less than the smallest individual resistor.
    1/R_total = 1/R1 + 1/R2 + 1/R3 + ...
  • Voltage Stays the Same: Every branch in a parallel circuit is connected directly across the power source. This means the voltage across every resistor is identical to the source voltage.
  • Current Splits (Branch Current): The total current leaving the power source splits up among the branches. Branches with lower resistance will let more current flow through them. You can find the current of a specific branch using Ohm's Law: I_branch = Voltage / R_individual.