Capacitor Parallel Calculator
Capacitors connected in parallel share the same voltage across every unit, so their charges add for a given voltage.
Enter Values
How to use this calculator
- Enter the value of each capacitor in microfarads (µF). Convert first if needed: 1 nF = 0.001 µF and 1 pF = 0.000001 µF.
- Fill Capacitor 1 and Capacitor 2; add the optional third value if you have three in parallel.
- Read the total capacitance — the equivalent single capacitor that replaces the parallel bank.
How it works
Capacitors connected in parallel share the same voltage across every unit, so their charges add for a given voltage. Because C = Q/V, the equivalent capacitance is simply the sum of the individual values: C_total = C1 + C2 + C3 + … Parallel wiring therefore always gives a LARGER total than any single capacitor — the opposite of resistors, and the opposite of capacitors in series.
This calculator sums the microfarad values you enter and returns the equivalent capacitance in µF. It assumes ideal capacitors and does not model equivalent series resistance (ESR), leakage or tolerance. The maximum working voltage of a parallel bank equals the lowest voltage rating among the capacitors, since each sees the full applied voltage.
Worked example
Three capacitors in parallel. You wire a 100 µF, a 220 µF and a 470 µF capacitor in parallel across the same two nodes. Capacitors in parallel add directly, so the total capacitance is 100 + 220 + 470 = 790 µF. Note the assembly's voltage rating is only as high as the lowest-rated single capacitor, not the sum.
Common mistakes
- Using the reciprocal (1/C) formula. That is for capacitors in SERIES. In parallel you add the values directly.
- Mixing units — entering some values in nF or pF alongside µF. Convert everything to microfarads first (1 nF = 0.001 µF, 1 pF = 1e-6 µF).
- Assuming the voltage rating adds. It does not: a parallel bank is limited to the lowest single-capacitor voltage rating, while only the capacitance adds.
Frequently asked questions
How do you calculate capacitors in parallel?
Add their capacitances directly: C_total = C1 + C2 + C3 + … For example 100 µF in parallel with 220 µF gives 320 µF. The total is always larger than any single capacitor.
Why do parallel capacitors add but series capacitors don't?
In parallel, every capacitor sees the same voltage, so their stored charges add and capacitance sums. In series they share charge but split the voltage, so the reciprocals add (1/C_total = 1/C1 + 1/C2 + …), giving a smaller total. Use the Capacitor Series Calculator for that case.
Does the voltage rating increase when I put capacitors in parallel?
No. Only the capacitance adds. Each capacitor still sees the full applied voltage, so the safe working voltage of the bank is the lowest voltage rating among the capacitors.
What units should I use?
Enter every value in microfarads (µF). If a part is marked in nanofarads or picofarads, convert first: 1 nF = 0.001 µF and 1 pF = 0.000001 µF.
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Tip: Enter any known values to calculate the remaining results.
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