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.
How to Use
- Pick series or parallel topology.
- Add one entry per capacitor. Values accept suffixes: 100nF, 22uF, 1pF.
- Enter applied voltage to compute charge, energy, and per-capacitor voltage distribution.
- Series: total capacitance < smallest member. Parallel: total = sum.
Show Work
Formulas
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.
About the Capacitor Calculator (Series/Parallel)
Need a hand with electronics and circuit design? The Capacitor Calculator (Series/Parallel) does the work for you — free, and right here in your browser. 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.
How it works
Type your numbers into the boxes. The answer shows up right away — you do not have to press a button. If you change a number, the answer changes too. So you can try different numbers and watch what happens, or check an answer you worked out yourself. Just make sure each box has the right kind of number in it.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
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.
How do I use the Capacitor Calculator (Series/Parallel)?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Is it free? Does it work without internet?
Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.
Where does my data go?
Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.
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.
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