Series Resistance Calculator
Add up resistors in series to find total circuit resistance instantly with this free electronics calculator in your browser.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the resistor values.
- Press Calculate.
How it works
Resistors in series simply add up: R1 + R2 + R3.
Worked example
10 Ω + 20 Ω. = 30 Ω.
Common mistakes
- Treating series like parallel — in series you simply add the values.
- Forgetting that series resistance always exceeds the largest single resistor.
Frequently asked questions
How do you calculate series resistance?
Add the values: Rt = R1 + R2 + R3 + … The same current flows through each, and the voltages across them add up to the supply.
Does resistor order matter in series?
No — total resistance is the same regardless of order, since the same current flows through each in turn.
Does the order of resistors matter in series?
No — in a series circuit the order doesn't change anything; the resistances simply add up.
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Cite this tool
Zerdly. (2026). Series Resistance Calculator. Retrieved from https://www.zerdly.com/tools/series-resistance-calculator/
Tip: Enter any known values to calculate the remaining results.
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