About the Capacitor Combination
The Capacitor Series & Parallel Calculator finds the total capacitance of two or more capacitors wired together, either in series or in parallel. Anyone building an electronic circuit, from a simple RC filter to a power supply smoothing bank, needs to know the combined value before ordering parts or checking a design against a target capacitance. Enter a comma-separated list of capacitor values in microfarads and pick a wiring configuration to get the combined result instantly.
How It Works
You select whether the capacitors are connected in series or in parallel, then type in their individual values in microfarads, separated by commas or spaces. The calculator parses that list, discards anything that isn't a valid positive number, and applies the matching formula to whatever values remain. The result is a single total capacitance figure in microfarads.
Formula & Methodology
To combine capacitors in series by hand, take the reciprocal of each value, add those reciprocals together, then take the reciprocal of that sum. Three capacitors of 10, 22, and 47 microfarads have reciprocals of about 0.1, 0.0455, and 0.0213; summed that's roughly 0.1667, and inverting gives about 6.0 microfarads. Parallel combination skips all of that: the values are simply added directly.
Examples
Series combination of three capacitors
With 10 microfarads, 22 microfarads, and 47 microfarads wired in series, the reciprocal-sum formula gives a total capacitance of about 6.00 microfarads, smaller than any single capacitor in the chain.
Parallel combination for higher capacitance
Wiring a 100 microfarad capacitor and a 220 microfarad capacitor in parallel simply adds their values, producing a total of 320 microfarads, useful when a single component can't supply enough capacitance for a power supply filter.
Advantages
- Switches between the series and parallel formulas automatically, so there's no risk of applying the wrong equation by hand.
- Accepts any number of capacitors in one entry field instead of forcing pairwise calculations for each additional component.
- Filters out invalid entries automatically, which keeps a messy or copy-pasted parts list from breaking the result.
Common Mistakes
- Applying the resistor combination formulas by mistake: capacitors work the opposite way, series capacitance uses the reciprocal-sum formula while parallel is a simple sum.
- Assuming the combined value will fall roughly in the middle of the listed values, when series combinations always land below the smallest capacitor.
- Mixing capacitance units, such as entering some values in nanofarads and others in microfarads, without converting them to the same unit first.
Edge Cases to Watch For
- Any entry that isn't a valid positive number is silently filtered out of the list before the calculation runs, so a stray comma or typo won't crash the result, it just gets ignored.
- If every entry is invalid or the field is left empty, the calculator returns an error asking for at least one positive capacitor value.
- A series total is always smaller than the smallest individual capacitor in the list, which can look surprising if you expect combining components to increase the value.
- A parallel total is always larger than the largest individual capacitor, since every value simply adds together.
Common Use Cases
- Hobbyist and student electronics builders checking a breadboard circuit's total capacitance before powering it on.
- Circuit designers selecting a combination of standard off-the-shelf capacitor values to hit a specific target capacitance.
- Technicians troubleshooting or replacing capacitor banks in power supplies and filter circuits.