# Capacitor energy from capacitance and voltage online calculator & Python code

TechOverflow calculators:
You can enter values with SI suffixes like 12.2m (equivalent to 0.012) or 14k (14000) or 32u (0.000032).
The results are calculated while you type and shown directly below the calculator, so there is no need to press return or click on a Calculate button. Just make sure that all inputs are green by entering valid values.

C

V

#### Formula

$$E = \frac{1}{2}\cdot{}C\cdot{}U_p^2$$

#### Python code

You can use the UliEngineering library like this:

from UliEngineering.Electronics.Capacitors import capacitor_energy
from UliEngineering.EngineerIO import auto_format, auto_print

# These are equivalent:
energy = capacitor_energy("100 uF", "24 V") # energy = 0.0288 (J)
energy = capacitor_energy(100e-6, 24.0) # energy = 0.0288 (J)

# ... or get out a human-readable value:
energy_str = auto_format(capacitor_energy, "100 uF", "24 V") # "28.8 mJ"
# ... or print directly
auto_print(capacitor_energy, "100 uF", "24 V") # prints "28.8 mJ"


In case you can’t use UliEngineering, use this Python function:

def capacitor_energy(capacitance, voltage):
return 0.5*capacitance*voltage*voltage

# Usage example:
print(capacitor_energy(100e-6, 24.0)) # prints 0.0288 (J)