Math & Science
Capacitor Calculator
Calculate reactance, energy, and RC constants
Formulas and edge cases are reviewed against authoritative references before publication. For methodology, editorial standards, or corrections, use the links below.
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
Inputs
- Capacitance
- Frequency
- Voltage
- Resistance
Results
- Reactance
- Stored Energy
- Time Constant
- Cutoff Frequency
Quick mental math is convenient, but it introduces errors. The Capacitor Calculator eliminates that risk by computing the exact result from your inputs. Provide capacitance, frequency, voltage and resistance to get started. The tool derives reactance, stored energy, time constant and cutoff frequency from your entries. People frequently need to calculate reactance, energy, and rc constants but lack a quick way to do it — this tool fills that gap. For large or small numbers, scientific notation keeps things readable and reduces mistakes.
Mathematical tools turn abstract formulas into concrete answers you can verify and apply. E = ½CV². A 1000µF cap at 50V stores 1.25 joules. Every calculator on this page uses a well-defined formula — the same one you would find in a textbook, applied instantly. Many practical problems — from engineering to daily budgets — reduce to straightforward arithmetic once you identify the right formula. Results are rounded for display; the underlying computation retains full precision.