Parallel Resistor Calculator
Find equivalent resistance for two or three ideal resistors in parallel.
Formula
1/R = 1/R₁ + 1/R₂ (+ 1/R₃).
Resistance R1: 100 Ω · Resistance R2: 100 Ω · Resistance R3: 100 Ω · Equivalent resistance ≈ 1÷(1÷(100 Ω)+1÷(100 Ω))
How to use
- Choose two or three resistors.
- Enter each positive resistance; R3 is ignored in two-resistor mode.
- Read equivalent resistance in ohms.
Examples
- 100 Ω parallel with 100 Ω gives 50 Ω.
Frequently asked questions
Can I use more resistors?
Combine a group, then use its equivalent resistance as one input.
Are wire and temperature effects included?
No. The model assumes fixed ideal resistances.
Can I enter a short circuit?
No. This calculator requires positive resistances.
Sources
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