Capacitor Calculator (Series/Parallel)

Combine capacitors in series or parallel to find total capacitance, energy stored, charge, and voltage distribution. Enter any number of capacitors with optional voltage ratings.

Calculator Electronics Updated Apr 18, 2026
How to Use
  1. Pick series or parallel topology.
  2. Add one entry per capacitor. Values accept suffixes: 100nF, 22uF, 1pF.
  3. Enter applied voltage to compute charge, energy, and per-capacitor voltage distribution.
  4. Series: total capacitance < smallest member. Parallel: total = sum.
Input
pF, nF, uF OK
V
Presets
Circuit
Total C
Energy
Charge
Count

Show Work

Add capacitors to see combination.

Formulas

Parallel Total
C_total = ΣCᵢ
Capacitances sum directly.
Series Total
1/C_total = Σ(1/Cᵢ)
Reciprocal sum — total < smallest member.
Two in Series
C = (C₁ × C₂) / (C₁ + C₂)
Convenient 2-element shortcut.
Energy
E = ½ × C × V²
Joules stored in the electric field.
Charge
Q = C × V
Coulombs; same Q on each cap in series.
Series Voltage
Vᵢ = Q / Cᵢ
Smaller caps get more voltage.

History of Capacitor Combinations

The mathematics of series and parallel capacitor combinations follow directly from conservation of charge and Kirchhoff's voltage law, both established by the mid-1840s. In parallel, each capacitor holds its own charge Qi = CiV at the common voltage V, and total charge adds: Ctotal = ΣCi. In series, the same charge Q flows into every capacitor (series implies same current, same charge), and voltages add: 1/Ctotal = Σ(1/Ci) — the reciprocal sum familiar from parallel resistors.

This inverse symmetry between resistor and capacitor combinations was one of the first "dualities" to appear in circuit theory. When Oliver Heaviside formalized the impedance concept in the 1890s, the duality became exact: replacing R with 1/(jωC) in any resistor formula gives the capacitor equivalent, which is why capacitor series/parallel math looks "backwards" compared to resistor math. The pattern generalizes — inductors (jωL) combine like resistors do; capacitors (1/jωC) combine inversely — and is the basis of every filter synthesis textbook.

About This Calculator

Choose series or parallel, add as many capacitors as you need, pick engineering units (pF, nF, µF), and this calculator returns the equivalent capacitance plus energy stored at a reference voltage. For mixed banks (some series, some parallel), break the network into sub-blocks and combine step by step.

Practical reminder: in parallel, the lowest voltage rating limits safe operation. In series, real caps rarely share voltage equally because leakage currents differ — use balancing resistors or matched caps where voltage is close to the rating. Everything runs client-side; no values leave your browser.

Frequently Asked Questions

Why is series capacitance less?

In series, the voltage divides across each cap in inverse proportion to capacitance. The total charge passes through each equally, but each stores fewer coulombs per volt — so effective capacitance shrinks. 1/C_total = Σ(1/Cᵢ).

Why does parallel just add?

Parallel caps all see the same voltage, and each stores its own charge. Total charge = sum of individual charges = V × ΣCᵢ. Total capacitance = sum.

Why combine capacitors at all?

Series: to get higher voltage rating (voltage divides). Parallel: to get higher total capacitance, lower ESR, or specific exact values from common parts.

Does voltage rating add in series?

Ideally yes — if you put two 16V caps in series, the combination can safely handle 32V. In practice, leakage current differences cause unbalanced voltage distribution, so add balancing resistors across each cap in high-voltage series strings.

How do I get odd values?

E.g., need 47nF but only have 100nF and 22nF on hand: 100nF ∥ 22nF = 122nF (won't work); 100nF in series with 22nF = 18nF (won't work). Use the calculator to find combos that land on what you need.

Common Use Cases

Power Supply Filtering

Parallel several 100µF caps near the load to reduce ESR and improve transient response, with one 10µF for higher-frequency bypassing.

High-Voltage Series Strings

Build an energy-storage bank for a coil gun or voltage multiplier by series-stacking 450V electrolytics with balancing resistors.

Precision Tuning

Fine-tune an oscillator by adding a small cap in parallel to an inexact standard value to hit a specific LC resonance.

Audio Crossover

Speaker crossover caps often need odd values — combine parallel electrolytics or film types to hit the design value.

Bypass Cap Optimization

High-speed digital design: parallel 100nF + 10nF + 1nF gives wide-band bypass performance, with each cap self-resonating at different frequencies.

Last updated: