Capacitor Charge Calculator
Calculate Capacitor Charge values for science, physics, chemistry, and engineering problems.
This capacitor charge calculator finds the electric charge and energy stored in a capacitor, based on its capacitance and the voltage applied across it.
Enter the capacitance and voltage, and the calculator returns the stored charge and energy.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| 100 μF capacitor at 12V | Q = 1.2 mC, E = 7.2 mJ | Q = 100×10⁻⁶ × 12 = 1,200 μC = 1.2 mC. E = 0.5 × 100×10⁻⁶ × 12² = 7,200 μJ = 7.2 mJ. |
| 470 μF capacitor at 5V | Q = 2.35 mC, E = 5.875 mJ | Q = 470×10⁻⁶ × 5 = 2,350 μC = 2.35 mC. E = 0.5 × 470×10⁻⁶ × 5² = 5,875 μJ ≈ 5.875 mJ. |
Charge and Energy Formulas
Stored charge: Q = CV, where C is capacitance (farads) and V is voltage. Stored energy: E = (1/2)CV^2. Notice that energy depends on voltage squared, so doubling the voltage across a capacitor quadruples the stored energy, even though it only doubles the stored charge.
What Capacitance Represents
Capacitance measures a capacitor's ability to store charge per unit of voltage - a larger capacitance stores more charge at the same voltage. Capacitors are commonly used for smoothing power supplies, timing circuits, and storing energy for quick release, unlike batteries which store much more energy but release it more slowly.
How to Use the Capacitor Charge Calculator
- Open the Capacitor Charge Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the capacitor charge calculator works.
Frequently Asked Questions
How do you calculate the charge stored in a capacitor?
Use Q = CV, where C is capacitance in farads and V is the voltage across the capacitor.
How do you calculate the energy stored in a capacitor?
Use E = (1/2)CV^2 - note that energy scales with the square of voltage, so doubling voltage quadruples stored energy.
What is the difference between charge and energy in a capacitor?
Charge (Q) is the total electric charge stored, measured in coulombs, while energy (E) is the work stored, measured in joules - they scale differently with voltage, since energy involves voltage squared.
How do I use this capacitor charge calculator?
Enter the known values, review the units or settings, and the calculator updates the result instantly. The formula and example on this page show how the answer is produced.
What does the Capacitor Charge Calculator calculate?
Calculate Capacitor Charge values for science, physics, chemistry, and engineering problems. It is designed for fast browser-based calculations without sign-up, downloads, or manual spreadsheet setup.
What formula does this capacitor charge use?
The formula is: Q = CV; E = ½CV². The capacitor's ability to store electrical charge was discovered accidentally in 1745-46 by Dutch physicist Pieter van Musschenbroek at Leiden University (with the device becoming known as the Leyden jar) and independently by German cleric Ewald Georg von Kleist - one of the earliest devices capable of storing an electric charge, over a century before capacitance was formally quantified and named by Michael Faraday, for whom the SI unit of capacitance, the farad, is named.
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Last updated: September 27, 2026.