Capacitance Calculator
Two capacitors combine in exactly the opposite way resistors do — parallel capacitance simply adds, while series capacitance behaves like the reciprocal-sum rule resistors use in parallel.
Inputs
Result
32 µF
How the capacitance calculator works
Parallel: total capacitance = C1 + C2 — capacitors in parallel add directly.
Series: total capacitance = (C1 × C2) ÷ (C1 + C2) — the same reciprocal-style combination rule used for resistors in parallel.
Worked example: C1 = 10 µF, C2 = 22 µF
- Parallel: 10 + 22 = 32 µF.
- Series: (10 × 22) ÷ (10 + 22) = 220 ÷ 32 ≈ 6.875 µF.
- Series combination is always smaller than the smallest individual capacitor — 6.875 µF is less than even the 10 µF alone.
Common mistakes to avoid
Applying the resistor combination rules directly
Capacitors combine the opposite way resistors do: series capacitors need the reciprocal-sum formula (like parallel resistors), while parallel capacitors simply add (like series resistors).
Expecting series capacitance to be an average of the two values
Series combination is always less than the smaller of the two capacitors, not an average — this surprises people used to resistor-parallel intuition where the combined value is always less than the smallest resistor too, but for a different underlying reason.
Frequently asked questions
Why does capacitance combine oppositely to resistance?
Capacitance relates to charge storage rather than current opposition. Series capacitors share the same charge but split voltage, which mathematically produces the reciprocal-sum relationship — the mirror image of how parallel resistors share voltage but split current.
What's a practical reason to put capacitors in series?
Voltage rating — putting two capacitors in series shares the applied voltage across them, letting the combination handle a higher voltage than either capacitor alone is rated for, at the cost of reduced total capacitance.
Does capacitor combination depend on frequency, like impedance does?
No — capacitance itself (in farads) is a fixed property based on how the capacitors combine; it's the resulting reactance (opposition to AC current) that additionally depends on frequency.
Can I combine more than two capacitors with this tool?
This tool handles the two-capacitor case directly; for more, combine two at a time and feed the running total back in as one of the two values for the next combination.
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