# Capacitive reactance online calculator & Python code

Use this online calculator to compute the reactance of a capacitor in Ω at a specific frequency given its capacitance.

TechOverflow calculators:
You can enter values with SI suffixes like 12.2m (equivalent to 0.012) or 14k (14000) or 32u (0.000032) as well as values with units (like 12V).
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.

F

Hz

#### Formula:

$$X_C = \frac{1}{2\pi fC}$$

#### Python code:

The preferred way is to use UliEngineering’s UliEngineering.Electronics.Reactance.capacitive_reactance:

from UliEngineering.Electronics.Reactance import *
# You can either pass strings like "150 pF" or values like 150e-12

capacitive_reactance("150 pF", "10 MHz") # returns 106.1032953945969

from UliEngineering.Electronics.Reactance import *
from UliEngineering.EngineerIO import *

# Compute value as a string
xc = auto_format(capacitive_reactance, "150 pF", "10 MHz") # "106 Ω"

# ... or print directly
auto_print(capacitive_reactance, "150 pF", "10 MHz") # prints "106 Ω"

In case you can’t use UliEngineering and you want to do it manually, here’s a minimal example:

import math
def capacitive_reactance(f, c):
"""Compute the capacitive reactance"""
return 1./(2*math.pi*f*c)