Parallel Resistor Calculator
Calculate the equivalent resistance of up to 5 resistors connected in parallel. Enter resistor values in ohms and get the total resistance instantly.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Parallel Resistor Calculator
- Enter resistor values in the input fields labeled R1 through R5. Type the resistance in ohms (Ω) — for example,
100or220. Only non-negative numbers are accepted. - Provide at least two values to calculate a meaningful result. You can leave unused fields blank.
- Click the "Calculate" button to compute the equivalent parallel resistance.
- View the result displayed in ohms (Ω) along with the step-by-step formula showing how the equivalent resistance was derived.
- If you see an error, check that all entered values are non-negative numbers and that no resistor is zero (which would indicate a short circuit).
Tip: Use decimal values if needed (e.g., 10.5 for 10.5 Ω). The calculator works with any positive resistance.
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Frequently Asked Questions
The equivalent resistance of resistors in parallel is given by 1/Req = 1/R1 + 1/R2 + ... + 1/Rn. Then Req = 1 / (sum of reciprocals).
Zero ohms would represent a short circuit, making the equivalent resistance zero. The calculator will show an error because it is not a valid resistor value.
This calculator supports up to 5 resistors. For more, you can use multiple calculations or a more advanced tool.