Parallel Resistor Calculator

Calculate the equivalent resistance of resistors connected in parallel. In parallel circuits, the total resistance is always less than the smallest individual resistance.

Parallel Resistor Circuit

                    ┌─── R1 ───┐
            ────────┤           ├────────
                    ├─── R2 ───┤
                    ├─── R3 ───┤
                    └─── R4 ───┘
                    
    Formula: 1/Rtotal = 1/R1 + 1/R2 + 1/R3 + 1/R4

Parallel Resistors

About Parallel Resistors

When resistors are connected in parallel, they provide multiple paths for current flow. The total resistance is always less than the smallest individual resistance.

Key Properties:

  • Lower Total Resistance: Always less than the smallest resistor
  • Same Voltage: Each resistor has the same voltage across it
  • Current Division: Current divides inversely proportional to resistance
  • Independent Operation: If one resistor fails, others continue to work

Applications:

  • Current divider circuits
  • Reducing total resistance
  • Increasing current capacity
  • Redundancy in critical circuits

Special Cases:

  • Two equal resistors: Rtotal = R/2
  • Many equal resistors: Rtotal = R/n (where n = number of resistors)
  • One very small resistor: Total ≈ smallest resistor value