Capacitor & Inductor Network Calculator
Total capacitance or inductance in series or parallel, the voltage each series capacitor takes, charge and energy at a voltage, and reactance at a frequency.
The equivalent value of a bank of capacitors or coils, with the uneven voltage split across series capacitors made visible so ratings can be checked before a part fails.
Example: 10 µF and 22 µF in series make 6.875 µF; at 12 V the 10 µF part takes 8.25 V and the 22 µF only 3.75 V. In parallel they make 32 µF. Inductors behave the other way round.
Capacitors add in parallel.
Inductors add in series.
The two combination rules, why series capacitors are the dangerous case, and what the ideal model leaves out.
The combination rules
Capacitors in parallel share the same voltage and their plate areas add, so C = ΣC. In series they carry the same charge and their voltages add, which gives 1/C = Σ1/C — the total is smaller than the smallest. Inductors are the mirror image: series coils carry the same current and their voltages add (L = ΣL), parallel coils share the voltage (1/L = Σ1/L). The same reciprocal arithmetic as resistors, applied the other way round for capacitors.
Series capacitors and voltage rating
Because series capacitors carry the same charge Q = C_total × V, each one sees V_i = Q ÷ C_i: the smallest capacitor takes the largest share of the voltage. Two unequal parts in series can put well over half the supply across the smaller one, so the page lists every share and flags an uneven split. With DC the split also drifts with leakage current, which is why series electrolytics are fitted with balancing resistors. Energy per part is ½CV_i², and the bank total is ½C_totalV².
Ideal parts, and reactance
No ESR, ESL, leakage or tolerance is modelled, and inductors are assumed not to couple — coils mounted close together share flux and the series total changes by twice the mutual inductance. The reactance at a frequency you enter is 1 ÷ 2πfC or 2πfL for the combined value, the figure needed for filters and impedance matching. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- Series and parallel combination of capacitors and inductors — standard circuit theory (e.g. Nilsson & Riedel, Electric Circuits, chapter 6)
Last reviewed 19 September 2026. How results are checked: How we verify.