Capacitance Calculator

About Capacitance Calculator

Our Capacitance Calculator helps you quickly calculate total capacitance for parallel and series circuits, plate capacitors, and energy storage. Perfect for electronics engineers, students, hobbyists, and anyone working with capacitors in electrical circuits. Get instant results in multiple units including Farads, microfarads, nanofarads, and picofarads.

How to Use the Capacitance Calculator

1. Select calculation mode (Parallel, Series, Plate Capacitor, or Energy Storage)
2. Choose your preferred unit (F, mF, µF, nF, or pF)
3. Enter capacitor values or plate dimensions
4. Click "Calculate" to get instant results
5. View results in all common units simultaneously
6. Copy results to clipboard for easy sharing
7. Try quick examples to see how it works

What is Capacitance?

Capacitance is the ability of a component or circuit to store electrical charge. It's measured in Farads (F) and represents the ratio of electric charge stored to the voltage across the capacitor. A capacitor with higher capacitance can store more charge at a given voltage.

Calculation Modes

Parallel Capacitors

When capacitors are connected in parallel, their capacitances add directly. The total capacitance is the sum of all individual capacitances:

Formula: C_total = C₁ + C₂ + C₃ + ...

• Increases total capacitance
• Voltage across each capacitor is the same
• Used to increase energy storage capacity

Series Capacitors

When capacitors are connected in series, the reciprocals of their capacitances add. The total capacitance is always less than the smallest individual capacitor:

Formula: 1/C_total = 1/C₁ + 1/C₂ + 1/C₃ + ...

• Decreases total capacitance
• Charge on each capacitor is the same
• Used to increase voltage rating

Plate Capacitor

Calculate capacitance based on physical dimensions and material properties:

Formula: C = ε₀ × εᵣ × A / d

• ε₀: Permittivity of free space (8.854 × 10⁻¹² F/m)
• εᵣ: Relative permittivity of dielectric material
• A: Plate area in square meters
• d: Distance between plates in meters

Energy Storage

Calculate the energy stored in a capacitor and the charge it holds:

Energy Formula: E = ½CV²

Charge Formula: Q = CV

• Energy is measured in Joules (J)
• Charge is measured in Coulombs (C)
• Energy increases with the square of voltage

Capacitance Units

• Farad (F): Base unit - very large, rarely used in practice
• Millifarad (mF): 10⁻³ F - used in supercapacitors
• Microfarad (µF): 10⁻⁶ F - common in power supplies and audio
• Nanofarad (nF): 10⁻⁹ F - used in RF and timing circuits
• Picofarad (pF): 10⁻¹² F - used in high-frequency circuits

Common Capacitor Types and Values

• Ceramic Capacitors: 1 pF to 1 µF - general purpose, stable
• Electrolytic Capacitors: 1 µF to 10,000 µF - high capacitance, polarized
• Film Capacitors: 100 pF to 10 µF - precise, low loss
• Tantalum Capacitors: 0.1 µF to 1000 µF - compact, stable
• Supercapacitors: 1 F to 10,000 F - energy storage, backup power

Dielectric Materials

The dielectric material between capacitor plates affects capacitance:

• Air/Vacuum: εᵣ = 1.0 - baseline reference
• Paper: εᵣ = 3.7 - vintage capacitors
• Teflon: εᵣ = 2.1 - low loss, stable
• Polyester: εᵣ = 3.3 - common film capacitors
• Glass: εᵣ = 4-10 - high voltage applications
• Ceramic: εᵣ = 10-10,000 - wide range, compact
• Aluminum Oxide: εᵣ = 8-10 - electrolytic capacitors

Applications of Capacitors

• Power Supply Filtering: Smooth DC voltage by removing ripple
• Energy Storage: Store energy for flash photography, backup power
• Timing Circuits: RC circuits for oscillators and timers
• Signal Coupling: Pass AC signals while blocking DC
• Decoupling: Reduce noise in power supply lines
• Motor Starting: Provide starting torque for AC motors
• Tuning Circuits: Select frequencies in radios and filters
• Power Factor Correction: Improve efficiency in AC systems

Practical Design Tips

• Always check voltage rating - use capacitors rated at least 50% above operating voltage
• Consider temperature coefficient for precision applications
• Electrolytic capacitors are polarized - observe polarity markings
• Use ceramic capacitors for high-frequency decoupling
• Parallel multiple smaller capacitors for better high-frequency performance
• Account for ESR (Equivalent Series Resistance) in power applications
• Consider aging effects - electrolytic capacitors degrade over time

Capacitor Behavior in Circuits

• DC Circuits: Capacitor charges to supply voltage, then blocks current
• AC Circuits: Capacitor allows AC to pass, impedance decreases with frequency
• Charging: Exponential rise following V(t) = V₀(1 - e^(-t/RC))
• Discharging: Exponential decay following V(t) = V₀e^(-t/RC)
• Time Constant: τ = RC (time to charge/discharge to 63.2%)

Safety Considerations

• Large capacitors can store dangerous amounts of energy
• Always discharge capacitors before handling
• Use appropriate discharge resistor (not a short circuit)
• High-voltage capacitors can remain charged for extended periods
• Observe polarity on electrolytic and tantalum capacitors
• Exceeding voltage rating can cause catastrophic failure

Frequently Asked Questions

Advanced Topics

• Parasitic Capacitance: Unwanted capacitance in circuits and components
• ESR and ESL: Equivalent Series Resistance and Inductance affect performance
• Self-Resonance: Frequency where capacitor behaves as resonant circuit
• Dielectric Absorption: Residual charge after discharge
• Aging Effects: Capacitance drift over time, especially in electrolytics

Calculation Examples