Series & Parallel Resistance Calculator

Series resistances add; parallel resistances add as reciprocals.

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Formula

Series: R = R₁ + R₂ + …
Parallel: 1/R = 1/R₁ + 1/R₂ + …

Example calculation

10, 20, 30 Ω → 60 Ω series, 5.45 Ω parallel.

Practical HVAC use

Heater element banks and sensor circuits.

Common mistakes

Assuming parallel total is an average — it's always less than the smallest.

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Educational tool. Results are estimates from the stated formulas; always confirm with manufacturer data and the code adopted in your jurisdiction. All calculators