Series Capacitance Calculator
The Series Capacitance Calculator computes series capacitance from the relation total series capacitance = 1 / (1 / C1 + 1 / C2). It takes 2 inputs (capacitor 1 in microfarads, capacitor 2 in microfarads) and returns the series capacitance. These tools cover a mixed set of everyday calculations that do not belong to one subject heading: a physical quantity such as density, work done or power, components combined in series, a drive ratio, or a chance-based draw. They suit students and hobbyists, people building or repairing something at home, and anyone who wants a single number quickly without building a spreadsheet. Enter your values below and the result updates instantly, and you can share a permalink that pre-fills the exact calculation. Each result follows directly from the figures you type in, so confirm what every field is asking for, including its unit where one applies, before you read anything into the answer. For the chance-based tools, set the range and the number of values first, then take the run as it comes, because each run is independent of the one before it. For example, with capacitor 1 = 20 microfarads, capacitor 2 = 60 microfarads, the series capacitance works out to 15, and the worked example further down the page shows every step so you can follow the arithmetic and reproduce it by hand. The method is the standard form documented by NIST: SI units, and the figure above each result carries the date it was last verified. Being a mixed group rather than one discipline, this set has no single limitation: the physical and electrical results are arithmetic on the values you supply and assume the clean, idealised arrangement the formula describes, so a real material, component or drivetrain can behave differently in use, while the chance-based results are ordinary computer-generated randomness, fine for a game or an informal draw but not for security keys, wagering, or anything that has to be provably fair.
With Capacitor 1 = 20 microfarads, Capacitor 2 = 60 microfarads, the result is 15.
Applies to: any numeric inputs. Method source: NIST: SI units, checked 2026-06-23.
The formula
total series capacitance = 1 / (1 / C1 + 1 / C2)
Worked example
With Capacitor 1 = 20 microfarads, Capacitor 2 = 60 microfarads:
- Reciprocal sum = 1/20 + 1/60 = 0.06666666666666667
- Total = 1 / 0.06666666666666667 = 15 microfarads
- Series Capacitance = 15
This worked example is one of the automated golden-value tests this calculator must pass before it can publish.
What this assumes
- Inputs are real numbers in the units shown.
- The result is the exact value of total series capacitance = 1 / (1 / C1 + 1 / C2); general information, not professional advice.
Frequently asked questions
What formula does this use?
total series capacitance = 1 / (1 / C1 + 1 / C2), the standard form documented by NIST: SI units.
Does the result ever change over time?
No. This is a pure formula with no external rate, so the same inputs always give the same result.
Official sources and verification
- Method: NIST: SI units, checked 2026-06-23.
Reviewed by the CalculatorHub team, edited by James Graham, 2026-06-23. See our methodology. General information, not professional advice.