Calculate the opposition to alternating current flow offered by a capacitor.
Circuit Parameters
Calculation Results
Enter frequency and capacitance
About this calculator
Quick Reference
XcCapacitive Reactance (Ohms)
fFrequency (Hertz)
CCapacitance (Farads)
π≈ 3.14159
Overview
Capacitive reactance is an opposition to the change of voltage across an element. It is inversely proportional to the signal frequency and the capacitance.
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Pro Tips
At DC (0 Hz), capacitive reactance is infinite—the capacitor acts as an open circuit.
As frequency increases, reactance decreases, allowing more AC to pass.
Reactance is measured in Ohms (Ω), just like resistance, but it's frequency-dependent.
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Fun Facts
"Capacitors are often used in crossover circuits in speakers to block low frequencies from tweeters."
"The formula was popularized with the rise of radio technology in the early 20th century."
"In an ideal capacitor, the current leads the voltage by exactly 90 degrees."
