Series and Parallel Capacitor Calculator

Find the combined capacitance of capacitors wired in series or parallel — the reverse of how resistors combine.

How to Use the Series and Parallel Capacitor Calculator

Choose Series or Parallel, then enter a value in µF for each capacitor in the list — add more rows or remove down to one. The combined total updates as soon as any value or the mode changes.

The Opposite of How Resistors Combine

This is the single most common mix-up in basic circuit analysis: resistors in parallel get smaller and resistors in series just add up, but capacitors do the exact reverse. Capacitors in parallel add directly, and capacitors in series behave like the harmonic, always-smaller-than-the-smallest relationship resistors follow in parallel:

Series:   1 ÷ Ctotal = 1 ÷ C1 + 1 ÷ C2 + ... + 1 ÷ Cn
Parallel: Ctotal = C1 + C2 + ... + Cn

The reason traces back to what each configuration physically does to plate area and separation. Wiring capacitors in parallel effectively enlarges the plate area available to store charge, and capacitance scales up directly with plate area — so parallel capacitance simply adds, the same intuitive way resistors in series add. Wiring them in series effectively stacks the gaps between plates end to end, increasing the total separation the field has to cross, and capacitance scales down as separation grows — which produces the same diminishing-returns harmonic relationship that parallel resistors follow.

Two identical 10 µF capacitors in parallel give a clean 20 µF; the same two in series give 5 µF — half, not double. If a series/parallel combined-capacitor result comes out larger for series than parallel, something's been read backward.