Capacitor Energy Calculator (Joules and Charge)
Enter the capacitance and voltage.
Your numbers
Your results
Stored energy (J)
Stored energy (J)
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Charge (mC)
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Energy released discharging to the lower voltage (J)
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Stored energy (mWh)
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Capacitor Energy Calculator (Joules and Charge) by TheCalcTools
How the Capacitor Energy Calculator (Joules and Charge) works
A capacitor stores energy E = ½CV² in its electric field, and charge Q = CV. Energy grows with the square of the voltage, so doubling the voltage stores four times the energy.
Large capacitors in power supplies and camera flashes can hold a dangerous charge long after power is removed. Discharge them safely through a suitable resistor.
The formula
E = ½ C V²; Q = C V
Worked example
Using the default values shown in the calculator:
| Capacitance (µF) | 4700 |
|---|---|
| Voltage (V) | 50 |
| Discharged down to (V) | 0 |
- 4700 µF at 50 V stores 5.8750 J and 235.000 mC of charge.
Result:
| Stored energy (J) | 5.8750 |
|---|---|
| Charge (mC) | 235.000 |
| Energy released discharging to the lower voltage (J) | 5.8750 |
| Stored energy (mWh) | 1.6319 |
Frequently asked questions
How much energy is in a 4700 µF capacitor at 50 V?
About 5.9 joules.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.