Calculate the total equivalent capacitance for circuits in series or parallel. Features dynamic input for multiple capacitors and automatic unit conversion (pF, nF, µF).
Capacitor Calculator
Equivalent Capacitance Formulas
In electrical engineering, combining capacitors allows you to achieve specific capacitance values and voltage ratings that might not be available in a single component. Note that the rules for capacitors are the opposite of those for resistors.
Parallel Configuration
Capacitors in parallel share the same voltage. The total capacitance is the sum of all individual capacitances.Ctotal = C₁ + C₂ + C₃ + ...
Series Configuration
Capacitors in series share the same charge. The reciprocal of the total capacitance is the sum of the reciprocals of each capacitance.1/Ctotal = 1/C₁ + 1/C₂ + 1/C₃ + ...
Capacitance Unit Conversion Table
Capacitance is measured in Farads (F), but since a Farad is a very large unit, we typically use smaller prefixes:
| Unit | Symbol | Multiplier (Farads) |
|---|---|---|
| Microfarad | µF | 10⁻⁶ (0.000001 F) |
| Nanofarad | nF | 10⁻⁹ |
| Picofarad | pF | 10⁻¹² |
Practical Context: Why Use Different Configurations?
When to use Parallel?
Use a parallel configuration when you need to increase total capacitance. This is common in power supply filtering where high storage capacity is required to smooth out voltage ripples. All capacitors in parallel must be rated for the full circuit voltage.
When to use Series?
Use a series configuration when you need to increase the voltage rating of your capacitor bank. For example, two 50V capacitors in series can theoretically handle 100V. However, remember that the total capacitance will decrease (it will be less than the smallest capacitor in the string).
Pro Tip: When placing capacitors in series to increase voltage rating, use identical capacitors and consider adding “balancing resistors” to ensure the voltage divides equally across them.