When to use this calculator
Add three resistors connected in series. The same current flows through all resistors in an ideal series circuit.
Explore the dc circuits & components calculators for other questions in this topic. For a related calculation, use the Transformer Voltage Calculator: Find ideal secondary voltage from primary voltage and turns ratio.
PUTTING IT INTO PRACTICE
Series Resistance: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| First resistance (Ω) | 10 |
| Second resistance (Ω) | 20 |
| Third resistance (Ω) | 30 |
| Result | 60 Ω |
- Check the input labels and enter the example values above.
- Apply the relationship: Total resistance = R₁ + R₂ + R₃.
- The result is 60 Ω, rounded for display.
How to interpret your result
The same current flows through all resistors in an ideal series circuit.
Ideal component models omit tolerances, heat and parasitic effects. Distinguish nominal energy from usable energy for batteries. Component ratings and installation requirements need separate manufacturer and design checks.
Frequently asked questions
Can these calculations select a safe installation rating?
No. They explain ideal relationships and do not include every thermal, protective or regulatory requirement.
How do I use the series resistance calculator?
Enter first resistance (ω), second resistance (ω), third resistance (ω). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Total resistance = R₁ + R₂ + R₃.
What should I check before using the result?
The same current flows through all resistors in an ideal series circuit.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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