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Capacitance Calculator

Calculate capacitance, charge, energy storage, and series/parallel combinations for capacitors. Supports multiple unit conversions with step-by-step solutions for physics and electronics.

Capacitance Calculator
C = Q / V  |  C = ε₀εᵣA / d  |  E = ½CV²
Select a calculation mode, enter the required values, and click Calculate. All units are convertible.
Result
Select a mode, enter values, and click Calculate
Tip: A capacitor stores energy in an electric field. The capacitance depends on plate area, separation distance, and the dielectric material between the plates. Larger area and higher permittivity increase capacitance; larger separation decreases it.

Capacitance Formulas & Related Equations

Core Formula

C = Q / V

Where C = capacitance (F), Q = charge (C), V = voltage (V)

Parallel Plate Capacitor

C = ε₀ × εᵣ × A / d

ε₀ = 8.85×10⁻¹² F/m, εᵣ = relative permittivity, A = area (m²), d = separation (m)

Energy Stored

E = ½ × C × V² = ½ × Q × V = Q² / (2 × C)

E = energy (J), C = capacitance (F), V = voltage (V), Q = charge (C)

Series & Parallel Combinations

Series: 1/Ct = 1/C₁ + 1/C₂ + 1/C₃ + ...

Total capacitance is less than the smallest individual capacitor

Parallel: Ct = C₁ + C₂ + C₃ + ...

Total capacitance is the sum of all individual capacitors

Unit Conversions

1 F = 10³ mF = 10⁶ μF = 10⁹ nF = 10¹² pF
1 C = 10³ mC = 10⁶ μC

Step-by-Step Examples

Example 1: Calculating Capacitance from Charge and Voltage

Problem: A capacitor stores 0.002 C of charge when connected to a 10 V battery. What is its capacitance?

  1. Formula: C = Q / V
  2. Values: Q = 0.002 C, V = 10 V
  3. Calculation: C = 0.002 / 10 = 0.0002 F
  4. Result: 0.0002 F = 200 μF
Example 2: Parallel Plate Capacitor

Problem: Two parallel plates have an area of 0.01 m² separated by 1 mm of air (εᵣ = 1). What is the capacitance?

  1. Formula: C = ε₀ × εᵣ × A / d
  2. Values: ε₀ = 8.85×10⁻¹², εᵣ = 1, A = 0.01 m², d = 0.001 m
  3. Calculation: C = (8.85×10⁻¹²)(1)(0.01) / 0.001
  4. Result: 8.85 × 10⁻¹¹ F = 88.5 pF
Example 3: Energy Stored in a Capacitor

Problem: A 100 μF capacitor is charged to 12 V. How much energy is stored?

  1. Formula: E = ½ × C × V²
  2. Convert: C = 100 μF = 0.0001 F
  3. Calculation: E = ½ × 0.0001 × 12² = ½ × 0.0001 × 144 = 0.0072 J
  4. Result: 7.2 mJ of energy stored
Example 4: Capacitors in Series and Parallel

Problem: Three capacitors (10 μF, 22 μF, 47 μF) are connected in series. What is the total capacitance?

  1. Formula: 1/Ct = 1/C₁ + 1/C₂ + 1/C₃
  2. Calculation: 1/Ct = 1/10 + 1/22 + 1/47 = 0.1 + 0.04545 + 0.02128 = 0.16673
  3. Result: Ct = 1/0.16673 = 6.00 μF (approximately)
  4. Check: In parallel, Ct = 10 + 22 + 47 = 79 μF

Common Dielectric Materials

Dielectric constants (relative permittivity) of common materials at room temperature.

Material Dielectric Constant (εᵣ) Dielectric Strength (V/mm)
Vacuum1.0000
Air (dry)1.00063,000
Paper (dry)3.516,000
Mica3.0–6.0100,000
Glass (pyrex)4.714,000
Porcelain5.0–7.010,000
Bakelite4.5–5.512,000
Polyethylene2.350,000
Polystyrene2.525,000
PVC3.540,000
Teflon (PTFE)2.160,000
Silicon Dioxide3.9500,000
Aluminum Oxide8.5300,000
Tantalum Pentoxide2750,000
Ceramic (Class 1)10–10010,000–50,000
Ceramic (Class 2)100–10,000+5,000–20,000
Distilled Water80
Titanium Dioxide85–1705,000

Note: Dielectric constants may vary with temperature, frequency, and material composition. Dielectric strength is the maximum electric field the material can withstand without breakdown.

Capacitance Calculator Features

Four Calculation Modes
Calculate capacitance from Q/V, parallel plate dimensions, energy storage, and series/parallel combos. Switch modes instantly.
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Multiple Unit Support
Supports farad, millifarad, microfarad, nanofarad, picofarad for capacitance. Charge in C/mC/μC. Distance in m/cm/mm. Area in m²/cm²/mm².
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Dielectric Reference Table
Quick reference table with dielectric constants and breakdown voltages for 18+ common materials from air to ceramics.
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Educational Examples
Step-by-step worked examples show the calculation process, unit conversions, and real-world applications in electronics.
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Mobile Optimized
Responsive design works perfectly on phones, tablets, and desktops for studying on the go.
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Privacy Protected
All calculations performed locally in your browser. No data is sent to any server.

How to Use the Capacitance Calculator

Step 1: Choose Your Calculation Mode

Use the mode buttons to select your calculation type. Choose between C = Q / V (capacitance from charge and voltage), Parallel Plate (geometric capacitance), Energy Storage (energy in a capacitor), or Series/Parallel (combined capacitance).

Step 2: Enter Your Values

Fill in the required input fields for your chosen mode. For the series/parallel mode, enter comma-separated capacitor values (e.g., "10, 22, 47"). Select appropriate units from the dropdown menus.

Step 3: Click Calculate

Press the Calculate button to compute your result. The answer will be displayed with the formula used, including unit conversions and step-by-step details.

Step 4: Explore More

Switch between the Calculator, Formula, Examples, and Dielectrics tabs to access formulas, worked examples, and a comprehensive table of dielectric materials.

Real-World Applications of Capacitors

Power Supply Filtering

Capacitors smooth out voltage ripple in power supplies. After rectification, large electrolytic capacitors filter the AC ripple to produce clean DC voltage for electronic devices.

Timing Circuits

RC timing circuits use capacitors and resistors to create time delays. The charge/discharge time constant τ = RC determines the timing in oscillators, blinkers, and pulse generators.

Energy Storage

Capacitors store electrical energy for rapid release. Applications include camera flashes (discharge in milliseconds), defibrillators, pulsed lasers, and regenerative braking systems in electric vehicles.

Coupling & Decoupling

Capacitors block DC while allowing AC signals to pass. Used for inter-stage coupling in amplifiers and decoupling power supply noise from sensitive ICs. Typical values range from 0.1 μF to 10 μF.

Power Factor Correction

Large capacitor banks are used in industrial power systems to correct power factor, reducing reactive power and improving energy efficiency. This saves money on electricity bills and reduces line losses.

Tuning & Resonance

Variable capacitors are used in LC tank circuits for tuning radios, filters, and oscillators. The resonant frequency f = 1/(2π√(LC)) determines which frequencies are selected or rejected.

Frequently Asked Questions (FAQ)

How do I calculate capacitance? +
Capacitance is calculated using the formula C = Q / V, where C is capacitance in farads, Q is charge in coulombs, and V is voltage in volts. For a parallel plate capacitor, C = ε₀ × εᵣ × A / d, where ε₀ = 8.85×10⁻¹² F/m is the permittivity of free space, εᵣ is the relative permittivity, A is the plate area, and d is the plate separation.
What is the unit of capacitance? +
The SI unit of capacitance is the farad (F). One farad equals one coulomb per volt (1 F = 1 C/V). In practice, farad is very large, so capacitance is commonly expressed in microfarads (μF, 10⁻⁶ F), nanofarads (nF, 10⁻⁹ F), and picofarads (pF, 10⁻¹² F). Electrolytic capacitors are typically μF to mF range, while ceramic capacitors are pF to nF range.
How do I calculate energy stored in a capacitor? +
The energy stored in a capacitor is calculated using E = ½ × C × V², where E is energy in joules, C is capacitance in farads, and V is the voltage. Alternatively, E = ½ × Q × V or E = Q² / (2 × C), where Q is the charge stored. The energy is stored in the electric field between the plates.
How do capacitors work in series vs parallel? +
In parallel, capacitances add directly: Ct = C₁ + C₂ + C₃ + ... This increases total capacitance. In series, reciprocals add: 1/Ct = 1/C₁ + 1/C₂ + 1/C₃ + ... This reduces total capacitance below the smallest individual value. Series connection also increases the overall voltage rating.
What is a dielectric and its effect on capacitance? +
A dielectric is an insulating material placed between capacitor plates. It increases capacitance by a factor equal to its relative permittivity (dielectric constant). Common dielectrics include air (εᵣ≈1), paper (εᵣ≈3.5), glass (εᵣ≈5-10), and ceramic (εᵣ≈10-10000+). Dielectrics also increase voltage ratings and reduce plate spacing effects.
How do I convert between capacitance units? +
Conversion factors: 1 F = 1000 mF, 1 F = 10⁶ μF, 1 F = 10⁹ nF, 1 F = 10¹² pF. To convert down (F to μF): multiply by 10⁶. To convert up (μF to F): divide by 10⁶. For example, 47 μF = 47,000 nF = 47,000,000 pF.
What is the permittivity of free space? +
The permittivity of free space (ε₀) is approximately 8.854187817×10⁻¹² F/m. It describes how an electric field influences a vacuum and appears in Coulomb's law, the parallel plate capacitance formula, and Maxwell's equations. Combined with the relative permittivity, ε = ε₀ × εᵣ gives the absolute permittivity of a material.
Why is capacitance important in electronics? +
Capacitors are essential in virtually all electronic circuits. Uses include energy storage (power supplies), filtering (smoothing voltage), coupling/decoupling signals, timing (RC circuits), tuning (radio frequency), power factor correction, and motor starting. Understanding capacitance is fundamental to circuit design.

About This Capacitance Calculator

Our capacitance calculator is a comprehensive tool designed for students, engineers, electronics hobbyists, and anyone who needs to perform capacitance-related calculations quickly and accurately. Whether you're studying physics, designing circuits, or working on electronics projects, this calculator provides everything you need.

Why Choose Our Capacitance Calculator?

  • Four Calculation Modes: Calculate capacitance from charge/voltage, parallel plate geometry, energy storage, and series/parallel combinations
  • Flexible Unit Support: Multiple units for capacitance, charge, voltage, area, and distance with automatic conversion
  • Comprehensive Reference Data: Dielectric constants and breakdown voltages for 18+ common materials
  • Educational Resources: Detailed formulas, step-by-step examples, and unit conversion guides
  • Real-World Context: Practical applications across electronics, power systems, and engineering
  • Privacy First: All calculations happen locally in your browser

Capacitance is a fundamental property in electronics and physics. Understanding how capacitors store charge and energy, and how their geometry and dielectric materials affect performance, is essential for circuit design, power systems, and countless engineering applications.

Important Note: Capacitance values can vary based on temperature, frequency, manufacturing tolerance, and aging. While our calculator provides accurate theoretical calculations, always verify critical circuit parameters with datasheets and calibrated instruments. This tool is for educational and general reference purposes.