Series and Parallel Resistor Calculator
Calculate equivalent resistance for common series and parallel resistor setups.
Inputs
Result
Example Inputs: Series: 100, 220, 330; Parallel: 100, 200
Example Output: Series total = 650 Ohms; Parallel total = 66.67 Ohms
Live Result: Enter values and click Calculate.
Formula
Series: Rtotal = R1 + R2 + ...; Parallel: Rtotal = 1/(1/R1 + 1/R2 + ...); 2-resistor shortcut: Rtotal = (R1 * R2)/(R1 + R2).
Worked Example
Use the example inputs and outputs above to walk through the calculation step-by-step.
FAQ
What is the difference between series and parallel?
Series adds resistances directly; parallel uses reciprocal sums.
How do I enter mixed networks?
Use expression mode on equivalent resistance pages with + for series and || for parallel, such as (100 + 220) || 330.
Can I use values like 4.7k?
Yes. Engineering notation is supported in resistor inputs.
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Formula Notes
This consolidated calculator covers both series and parallel resistor scenarios.
Worked Example
For two resistors in parallel, 100 and 200 ohms, Rtotal is 66.67 ohms.