# Parallel Resistors Calculator

Calculate total resistance of up to 5 resistors in parallel using 1/R = 1/R₁ + 1/R₂ + ... Free online parallel resistance calculator.

## What this calculates

When resistors are connected in parallel, the total (equivalent) resistance is always less than the smallest individual resistor. This calculator uses the formula 1/R_total = 1/R₁ + 1/R₂ + ... to find the combined resistance of up to five resistors in parallel. This is essential for circuit design and analysis.

## Inputs

- **Resistor 1 (R₁)** (Ω) — min 0
- **Resistor 2 (R₂)** (Ω) — min 0
- **Resistor 3 (R₃, optional)** (Ω) — min 0
- **Resistor 4 (R₄, optional)** (Ω) — min 0
- **Resistor 5 (R₅, optional)** (Ω) — min 0

## Outputs

- **Total Parallel Resistance** (Ω) — 1/R_total = 1/R₁ + 1/R₂ + ...
- **Total Resistance** (kΩ) — Resistance in kilohms
- **Resistors Used** — Number of resistors in calculation

## Frequently Asked Questions

**Q: How do you calculate parallel resistance?**

A: For resistors in parallel, use 1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + ... For two resistors, a shortcut is R_total = (R₁ × R₂)/(R₁ + R₂). The total resistance in a parallel circuit is always less than the smallest individual resistor because each additional path allows more current to flow.

**Q: Why is parallel resistance always less than the smallest resistor?**

A: Each parallel resistor provides an additional path for current to flow. More paths mean more total current for the same voltage, which by Ohm's law means lower total resistance. Think of it like opening additional lanes on a highway: more lanes mean less overall traffic resistance.

**Q: What happens if one parallel resistor has zero resistance?**

A: If any branch has zero resistance, all current flows through that branch (a short circuit), and the total parallel resistance becomes zero. This is why a short circuit in any parallel branch effectively bypasses all other branches.

**Q: How is parallel different from series resistance?**

A: In series, resistances simply add up: R_total = R₁ + R₂ + ... In parallel, the reciprocals add up: 1/R_total = 1/R₁ + 1/R₂ + ... Series resistance is always greater than any individual resistor, while parallel resistance is always less. Most real circuits use combinations of both.

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Source: https://vastcalc.com/calculators/physics/parallel-resistors
Category: Physics
Last updated: 2026-04-21