Calculators
Series & Parallel Capacitor Calculator
Combine capacitors in series or parallel and calculate equivalent capacitance.
Series & Parallel Capacitor Calculator tool
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About This Tool
Capacitors combine differently from resistors: parallel capacitances add directly, while series capacitances combine through their reciprocals. This calculator accepts two or more capacitor values, lets each value use its own common capacitance unit, and finds the equivalent capacitance for a pure series chain or pure parallel group. You can also enter an applied voltage to estimate the energy stored by the ideal equivalent capacitance. The calculation runs locally in your browser and is useful for electronics study, checking component substitutions, decoupling combinations, timing networks, and basic filter design.
How To Use It
- Choose whether all entered capacitors are connected in parallel or in series.
- Enter at least two capacitance values and choose the unit for each value. You can mix F, mF, µF, nF, and pF.
- Add or remove capacitor rows as needed, then read the equivalent capacitance in a convenient engineering unit.
- Optionally enter the voltage across the complete network to estimate ideal total stored energy. For real hardware, check individual capacitor voltage ratings and circuit-specific voltage sharing separately.
Examples
10 µF and 22 µF in parallel
Parallel capacitances add directly, so 10 µF + 22 µF gives an equivalent capacitance of 32 µF.
10 µF and 22 µF in series
For two capacitors in series, Ceq = C1C2/(C1+C2). The same 10 µF and 22 µF capacitors give approximately 6.875 µF.
Three decoupling values
100 nF, 1 µF, and 10 µF in parallel equal 11.1 µF by nominal capacitance. Real high-frequency behavior also depends on ESR, ESL, package, placement, and dielectric characteristics.
Useful Notes
Parallel capacitor formula
For capacitors connected across the same two nodes, Ceq = C1 + C2 + … + Cn. Each ideal capacitor has the same voltage, while the total stored charge is the sum of the branch charges.
Series capacitor formula
For a pure series chain, 1/Ceq = 1/C1 + 1/C2 + … + 1/Cn. For exactly two capacitors this simplifies to Ceq = C1C2/(C1+C2). The equivalent series capacitance is always smaller than the smallest individual capacitance.
Mixed capacitance units
The calculator converts each entry to farads before applying the network formula, so values such as 100 nF and 1 µF can be combined directly. Using explicit units helps avoid the million-fold errors that can occur when confusing µF, nF, and pF.
Stored energy
For an ideal equivalent capacitance C across voltage V, total stored energy is E = ½CV². This is an energy estimate for the complete network, not a substitute for checking individual capacitor voltage, ripple-current, thermal, or safety ratings.
Series voltage sharing
Ideal series capacitors carry equal charge, so their voltages are inversely related to capacitance. Real leakage differences and tolerances can make static voltage sharing unpredictable; high-voltage series stacks may require balancing components and appropriate engineering review.
Ideal model limitations
Real capacitors have tolerance, ESR, ESL, leakage, temperature dependence, aging, and sometimes strong capacitance change with applied voltage. Equivalent nominal capacitance is only one part of selecting a practical capacitor network.
FAQ
Why do capacitors add in parallel?
Parallel capacitors share the same voltage and their stored charges add. Because capacitance is charge divided by voltage, their capacitances therefore add directly.
Why is series capacitance smaller?
A series chain carries the same ideal charge on each capacitor while the individual voltage drops add. The reciprocal formula makes the equivalent capacitance smaller than the smallest capacitor in the chain.
Can I mix microfarads and nanofarads?
Yes. Each input has its own unit selector, and the calculator converts all values to farads internally before calculating the result.
Does putting capacitors in series simply add their voltage ratings?
Do not assume ideal equal voltage sharing in a real circuit. Leakage, tolerance, transients, and other effects can produce unequal voltage, so series high-voltage designs require appropriate component derating and balancing analysis.