Series Capacitance Calculator
Capacitors in series carry the same charge while their voltages add, so the combined capacitance is always less than the smallest single capacitor. Enter any number of capacitance values in farads, separated by commas or spaces. The calculator adds the reciprocals and inverts the sum to give the total series capacitance.
Series capacitance formula
1 / Ctotal = 1/C1 + 1/C2 + ... + 1/Cn
Ctotal = 1 / (sum of reciprocals)
Two-capacitor case: Ctotal = (C1 * C2) / (C1 + C2)
The reciprocal rule for series capacitors mirrors the rule for resistors in parallel.
Worked example
Three capacitors of 10, 22, and 47 microfarads (0.00001, 0.000022, 0.000047 F) in series: 1/Ctotal = 1/0.00001 + 1/0.000022 + 1/0.000047 = 100,000 + 45,455 + 21,277 = 166,731 per farad. Ctotal = 1 / 166,731 = 0.0000060 F, about 6.00 microfarads, less than the smallest (10 microfarads).
Series capacitance: frequently asked questions
How do capacitors combine in series?
Like resistors in parallel, capacitors in series add by reciprocals: 1/Ctotal = 1/C1 + 1/C2 + ... + 1/Cn. The total series capacitance is always smaller than the smallest individual capacitor.
Why is series capacitance smaller?
In series the same charge sits on each capacitor but the voltages add, so for a given charge the total voltage is larger, which means a smaller overall capacitance (capacitance is charge divided by voltage).
What is the two-capacitor shortcut?
For exactly two capacitors in series, Ctotal = (C1 C2) / (C1 + C2), the product over the sum. This calculator handles any number, but the two-capacitor form is convenient.
How do I enter capacitor values?
Enter each capacitance in farads, separated by commas or spaces. For microfarads convert first: 10 microfarads is 0.00001 F. The calculator combines every value listed.
Sources
- NIST: SI units (farad).
- The series-capacitance reciprocal-sum rule is a standard result of circuit theory.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.