Electronics
Reactance Calculator
Pick capacitive reactance, inductive reactance, or LC resonant frequency, then enter the component value and frequency to see the impedance a capacitor or inductor presents at that frequency.
Find capacitive or inductive reactance at a given frequency, or the resonant frequency of an LC pair.
Reactance and resonance
Xc = 1 / (2πfC) XL = 2πfL f₀ = 1 / (2π√(LC))
Capacitive reactance falls as frequency rises (capacitors pass high frequencies more easily); inductive reactance rises with frequency (inductors resist fast changes in current). At the resonant frequency of an LC pair, the two reactances cancel out.
How to use
- Choose whether you're solving for Xc, XL, or the resonant frequency of a specific L and C.
- Enter capacitance in microfarads and/or inductance in millihenries, matching the mode you selected.
- For Xc or XL, also enter the operating frequency; skip it when solving for resonance.
Example
Input: Capacitive mode: C = 100 µF, f = 60 Hz
Output: Xc ≈ 26.5 Ω
Student-friendly breakdown
This walkthrough emphasizes the most searched ideas for Reactance Calculator: reactance calculator, capacitive reactance calculator, inductive reactance calculator, lc resonant frequency calculator. Start with the formula above, then follow the guided steps to double-check your work. For quick revision, highlight the givens, plug into the equation, and finish by verifying your units.
Need more support? Use the links below to open the long-form guide, browse additional examples, or hop into adjacent calculators within the same topic — each one is a quick way to double-check your work or handle a related question without starting from scratch.
Deep dive & study plan
Reactance Calculator: Computes capacitive and inductive reactance, or LC resonant frequency. It's built around reactance calculator, capacitive reactance, resonant frequency, so you can go from a raw question to a checked answer without switching tools.
The math behind it: Capacitive reactance falls as frequency rises (capacitors pass high frequencies more easily); inductive reactance rises with frequency (inductors resist fast changes in current). At the resonant frequency of an LC pair, the two reactances cancel out. The core relationship is Xc = 1 / (2πfC) XL = 2πfL f₀ = 1 / (2π√(LC)), shown above the calculator so you can see exactly how your inputs turn into the result.
To use it well: (1) Choose whether you're solving for Xc, XL, or the resonant frequency of a specific L and C. (2) Enter capacitance in microfarads and/or inductance in millihenries, matching the mode you selected. (3) For Xc or XL, also enter the operating frequency; skip it when solving for resonance. Keep your units consistent as you go, and re-run a case you already know the answer to — it's the fastest way to catch a typo before it throws off a result you're relying on.
Worked example: entering Capacitive mode: C = 100 µF, f = 60 Hz returns Xc ≈ 26.5 Ω. Try swapping in your own numbers next, especially a case you're unsure about, before you use this for something that matters.
Quick retention checklist
- Speak the formula aloud (or annotate it) so the relationships stick.
- Write each step in your own words and compare with the numbered list above.
- Swap in new numbers for the Example to make sure the calculator (and your logic) handles edge cases.
- Check at least one related calculator below — it's the fastest way to confirm your numbers still line up from a different angle.
FAQ & notes
What's the difference between reactance and resistance?
Resistance dissipates energy as heat regardless of frequency. Reactance stores and releases energy (in an electric or magnetic field) and depends on frequency — at DC, capacitors act as an open circuit (infinite Xc) and inductors as a short (zero XL).
Why does resonant frequency matter?
At resonance, an LC circuit's impedance is at a minimum (series) or maximum (parallel), which is the basis for tuning filters, oscillators, and radio receivers to a specific frequency.
What formula does the Reactance Calculator use?
Capacitive reactance falls as frequency rises (capacitors pass high frequencies more easily); inductive reactance rises with frequency (inductors resist fast changes in current). At the resonant frequency of an LC pair, the two reactances cancel out.
How do I use the Reactance Calculator?
Choose whether you're solving for Xc, XL, or the resonant frequency of a specific L and C. Enter capacitance in microfarads and/or inductance in millihenries, matching the mode you selected. For Xc or XL, also enter the operating frequency; skip it when solving for resonance.