Parallel Capacitor Calculator
Equivalent capacitance for capacitors in parallel (Ceq = ΣC), in series (1/Ceq = Σ1/C) with per-capacitor voltage division, and series-parallel combinations via an expression parser — plus stored energy (E = ½CV²), charge, and a 3-digit capacitor code finder. 100% client-side.
| Capacitor | Value | Charge | Energy |
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Nearest standard value (E-series)
| Capacitor | Value | Voltage | % of V | Charge | Energy |
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In series the charge Q = Ceq × V is identical on every capacitor; voltage divides as Vi = Q/Ci — the smaller capacitor takes the larger voltage share.
| Capacitor | Value | Voltage | Charge | Energy |
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Formulas & worked examples
Worked examples
- Parallel: 100 nF + 220 nF = 320 nF. At 12 V the pair stores E = ½ × 320 nF × 12² = 23.04 µJ and holds Q = 3.84 µC total.
- Series: 100 nF + 220 nF → 1/Ceq = 1/100 + 1/220, so Ceq = 68.75 nF (smaller than either capacitor). At 12 V both hold Q = 825 nC; the 100 nF capacitor sees 8.25 V and the 220 nF capacitor sees 3.75 V.
- Combination: (100 nF + 220 nF) in series = 68.75 nF; in parallel with 470 nF → 538.75 nF. Type
(C1+C2)||C3in the Combination tab. - Code: marking “104” = 10 × 10⁴ pF = 100 nF.
Scope & boundaries
- Energy solver: to solve any one of E, C or V directly from E = ½CV², use the capacitor energy calculator — this page reports energy as a derived result of a capacitor network.
- Reactance: for Xc = 1/(2πfC) and frequency behavior, use the capacitive reactance calculator.
- Resistors: the dual network tool (reciprocal formula 1/Rt = Σ1/R) is the parallel resistor calculator.
- Units: F, mF, µF, nF and pF prefix conversion is covered by the electrical unit converter.
Ideal-capacitor model for education and quick design checks. Electrolytic capacitors in series need balancing resistors (see FAQ); verify safety-critical designs with proper engineering review.
Related tools
Frequently asked questions
What is the formula for capacitors in parallel?
Add them directly: Ceq = C1 + C2 + … + Cn. For example, 100 nF in parallel with 220 nF gives 320 nF. Every capacitor sees the same voltage, so the total charge is Q = Ceq × V and the stored energy is E = ½ × Ceq × V².
What is the formula for capacitors in series?
Use reciprocals: 1/Ceq = 1/C1 + 1/C2 + … + 1/Cn. For two capacitors this simplifies to Ceq = (C1 × C2)/(C1 + C2). Example: 100 nF in series with 220 nF gives 68.75 nF — always smaller than the smallest capacitor in the string.
Why is series capacitance smaller than the smallest capacitor?
In series the same charge sits on every capacitor, so the total voltage is the sum of the individual voltages. That is equivalent to increasing the plate separation of a single capacitor, which lowers capacitance. The result is always below the smallest value — for example, 100 nF and 220 nF in series give only 68.75 nF.
How does voltage divide across series capacitors?
Charge Q is identical on every series capacitor, so each voltage is Vi = Q/Ci with Q = Ceq × V. The smaller capacitor gets the larger share. Example: 100 nF and 220 nF in series across 12 V carry 825 nC, so the 100 nF capacitor sees 8.25 V and the 220 nF capacitor sees 3.75 V (8.25 + 3.75 = 12 V).
Is the charge the same on capacitors in series?
Yes. Whatever charge flows onto the first plate must induce the same charge on every following capacitor, so each series capacitor holds exactly Q = Ceq × V. In the 12 V example above, both the 100 nF and the 220 nF capacitor hold 825 nC. In parallel it is the opposite: voltage is shared and charge divides as Qi = Ci × V.
How do you calculate the energy stored in a capacitor?
E = ½ × C × V². For a 320 nF equivalent capacitance (100 nF + 220 nF in parallel) charged to 12 V, E = 0.5 × 320 nF × 144 = 23.04 µJ. For the series pair (68.75 nF) at 12 V it is only 4.95 µJ — series strings store less energy at the same voltage because their equivalent capacitance is smaller.
What does the capacitor code 104 mean?
Ceramic capacitors use a 3-digit code: the first two digits are the value, the third is the number of zeros, in picofarads. So 104 = 10 followed by 4 zeros = 100,000 pF = 100 nF. Other examples: 103 = 10 nF, 472 = 4.7 nF, 101 = 100 pF. Use the code finder tab above to decode any 3-digit marking.
Can I mix nF, µF and pF values in one calculation?
Yes — this calculator converts every entry to farads before combining, so you can freely mix picofarad, nanofarad, microfarad, millifarad and farad inputs. For instance, 1 µF + 1000 nF + 1,000,000 pF in parallel is exactly 3 µF. Results are auto-scaled to the most readable unit.
Can electrolytic (polarized) capacitors be used in series?
It is possible but needs care: use two identical capacitors so the voltage splits evenly, choose a voltage rating with margin on each (both must survive their share — for example at least 8.25 V on the 100 nF side of the 12 V series example), keep polarity correct, and add equal balancing resistors across each capacitor because leakage currents differ and can unbalance the division over time. For non-polarized film or ceramic capacitors none of this is needed.
How do you solve a series-parallel capacitor combination?
Reduce the innermost groups first: series groups with 1/Ceq = Σ(1/Ci), parallel groups with Ceq = ΣCi, then combine the results. Example: (100 nF + 220 nF) in series is 68.75 nF; in parallel with 470 nF that gives 68.75 + 470 = 538.75 nF. Type expressions like (C1+C2)||C3 into the Combination tab — '+' means series and '||' means parallel — and the tool also reports each capacitor's voltage, charge and energy.