Math & Science
Capacitor Calculator
Calculate reactance, energy, and RC constants
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Frequently asked questions
What is capacitive reactance?
Opposition to AC current that decreases with frequency - acts like resistance.
What is time constant?
Time for voltage to reach 63.2% of final value in RC circuit. 5τ ≈ fully charged.
How much energy can capacitors store?
E = ½CV². A 1000µF cap at 50V stores 1.25 joules.
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About this tool
This Capacitor Calculator turns your inputs into practical results. Provide Voltage, Capacitance, and Frequency to calculate Time Constant and Reactance.
Adjust values to compare scenarios and see how sensitive the result is. The calculation uses the numbers as entered, so double-check units and expect small differences from rounding in the displayed totals.