Capacitive Reactance Calculator
Calculate capacitive reactance from frequency and capacitance.
Interactive Electrical Calculator
Capacitive Reactance Calculator
Calculate capacitive reactance from frequency and capacitance.
Result
Enter values and calculate.
About the Capacitive Reactance Calculator
Use the Capacitive Reactance Calculator below to work through component-level calculations for resistors, capacitors and basic AC circuit behavior in seconds, right in your browser. Calculate capacitive reactance from frequency and capacitance. A resistor or capacitor picked without doing the calculation first is one of the most common sources of a circuit that doesn't behave as expected, or that damages an LED or IC.
It's aimed at electronics hobbyists, students and engineers designing or troubleshooting small circuits, who need a fast, reliable number without redoing the math by hand each time.
How the calculation works
Here is the relationship the calculator solves for you:
Xc = 1 / (2πfC).
Where each input maps to a field in the calculator above:
- Frequency in Hz.
- Capacitance in µF.
Every one of these values can be edited above, and the calculator updates the result the moment you press Calculate.
A worked example
For example, start with 50 Hz for frequency and 10 µF for capacitance. Those defaults are only a starting point — replace them with your own measured or nameplate values, then press Calculate to get a result specific to your situation.
When to use the Capacitive Reactance Calculator
Typical reasons people reach for the Capacitive Reactance Calculator:
- Picking a resistor or capacitor value for a specific circuit target.
- Checking a component combination before ordering parts or building a prototype.
- Working out a circuit's behavior at a specific frequency.
- Verifying a calculated value against a datasheet or standard component range.
Good practice: Reactance is frequency-dependent, so a capacitor or inductor calculation is only valid at the specific frequency it was calculated for.
Also worth knowing: Series and parallel combination rules are opposite for resistors and capacitors, which is a common source of mix-ups when switching between the two.
Frequently asked questions
What does the Capacitive Reactance Calculator calculate?
Calculate capacitive reactance from frequency and capacitance.
Is the result exact enough to build from?
The formula above is applied exactly to the values you enter, so the math itself is precise. Real-world results can still differ due to component tolerances, temperature, installation method, equipment efficiency and local code requirements, so treat the output as a strong planning estimate and verify final designs against manufacturer data and the electrical code that applies to your installation.
Do I need to sign up or install anything to use it?
No sign-up, download or installation is needed. The Capacitive Reactance Calculator runs entirely in your browser and is free to use.
Why not just estimate this instead of calculating it?
A resistor or capacitor picked without doing the calculation first is one of the most common sources of a circuit that doesn't behave as expected, or that damages an LED or IC.
Will this work for both metric and everyday values?
The Capacitive Reactance Calculator works on any modern browser, phone or desktop, and recalculates as soon as you press Calculate. If a result looks off, double-check that every field is filled in with the unit shown next to it (mixing up units, such as W with kW, is the most common cause of an unexpected answer) and re-enter the values.