Calculate capacitor energy, capacitance, or voltage from any two values in farads, volts, and watt-hours or joules, with steps shown.
Farad to Wh Formula
The following formula is used to convert capacitance and voltage into energy in watt-hours.
E (Wh) = \frac{C \cdot V^2}{2 \cdot 3600}Variables:
- E is the energy in watt-hours (Wh)
- C is the capacitance in farads (F)
- V is the voltage in volts (V)
To calculate the energy in watt-hours, square the voltage, multiply it by the capacitance, and then divide the product by twice the number of seconds in an hour (3600).
| Capacitance (F) | Wh @ 2.7 V | Wh @ 5 V | Wh @ 12 V |
|---|---|---|---|
| 0.1 | 0.000101 | 0.000347 | 0.002000 |
| 0.22 | 0.000223 | 0.000764 | 0.004400 |
| 0.33 | 0.000334 | 0.001146 | 0.006600 |
| 0.47 | 0.000476 | 0.001632 | 0.009400 |
| 0.5 | 0.000506 | 0.001736 | 0.010000 |
| 1 | 0.001013 | 0.003472 | 0.020000 |
| 1.5 | 0.001519 | 0.005208 | 0.030000 |
| 2 | 0.002025 | 0.006944 | 0.040000 |
| 2.5 | 0.002531 | 0.008681 | 0.050000 |
| 3 | 0.003038 | 0.010417 | 0.060000 |
| 5 | 0.005063 | 0.017361 | 0.100000 |
| 10 | 0.010125 | 0.034722 | 0.200000 |
| 20 | 0.020250 | 0.069444 | 0.400000 |
| 30 | 0.030375 | 0.104167 | 0.600000 |
| 50 | 0.050625 | 0.173611 | 1.000000 |
| 80 | 0.081000 | 0.277778 | 1.600000 |
| 100 | 0.101250 | 0.347222 | 2.000000 |
| 200 | 0.202500 | 0.694444 | 4.000000 |
| 300 | 0.303750 | 1.041667 | 6.000000 |
| 500 | 0.506250 | 1.736111 | 10.000000 |
| * Rounded to 6 decimals. Energy of a capacitor: E(Wh) = 0.5 × C(F) × V² ÷ 3600. Columns show Wh at common voltages (2.7 V, 5 V, 12 V). Note: 1 Wh = 3600 J. | |||
What is Energy in a Capacitor?
The energy stored in a capacitor is the electrical potential energy held within the electric field between the two plates of the capacitor. This energy can be released to power circuits and is especially useful in applications requiring quick bursts of energy. The unit of energy for capacitors is typically joules, but it can be converted to watt-hours for comparison with other energy storage devices like batteries.
How to Calculate Energy in Watt-Hours?
The following steps outline how to calculate the energy in watt-hours from capacitance and voltage.
- First, determine the capacitance (C) of the capacitor in farads.
- Next, determine the voltage (V) across the capacitor in volts.
- Use the formula E (Wh) = (C * V^2) / (2 * 3600).
- Finally, calculate the energy (E) in watt-hours.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Capacitance (C) = 5 farads
Voltage (V) = 12 volts
