Capacitor Series & Parallel Calculator
Combine capacitors in series or parallel, with working voltage and ripple-sharing notes.
Example: 2 capacitors in parallel (100 nF, 100 nF) gives 200 nF.
Formula
parallel: C = C₁ + C₂ + … series: 1/C = 1/C₁ + 1/C₂ + …Worked example
2 capacitors in parallel (100 nF, 100 nF) gives 200 nF.
C = C₁ + C₂ + …
C = 100 nF + 100 nF
200 nF
Parallel plates add area, so capacitance adds directly.
Frequently asked questions
Do capacitors in parallel add?
Yes — parallel capacitance is the simple sum, which is the opposite of resistors. Two 100 nF capacitors in parallel give 200 nF. Physically you are adding plate area.
How do I calculate capacitors in series?
Add the reciprocals and invert, exactly as you would for parallel resistors. Two 100 nF in series give 50 nF. Series stacking increases the effective plate separation, which reduces capacitance.
Does putting capacitors in series double the voltage rating?
In theory, but not reliably. The voltage divides according to leakage current, not capacitance, and leakage varies enormously between nominally identical parts. One capacitor can take most of the voltage and fail, which then overvolts the rest. Always fit balancing resistors across each capacitor.
Why do designs put a small ceramic next to a large electrolytic?
Because the electrolytic has significant series inductance and resistance, so it cannot respond to fast current transients. The small ceramic handles high frequencies while the electrolytic supplies bulk charge. In parallel their capacitances add, but it is their differing frequency behaviour that matters.
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