Quick answer
The resonant frequency of an LC circuit is f = 1 ÷ (2π√(LC)). With 1 mH and 1 µF, f = 5,032.9 Hz.
Enter the inductance and capacitance. The calculator returns the resonant frequency.
Related tools: Ohm's Law Calculator: Solve voltage, current or resistance. Parallel Resistor Calculator: Equivalent resistance of resistors in parallel and in series. Watt-Hours Calculator: Energy in watt-hours from power and time, or from amp-hours and voltage.
How to use the LC Resonant Frequency Calculator
- Enter inductance (mH) (above 0).
- Enter capacitance (µF) (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Inductance | A number, in mH | > 0 |
| Capacitance | A number, in µF | > 0 |
Formula and method
Formula
f = 1 ÷ (2π√(LC))
IEEE-754 double precision; shown to at most 6 decimal places.
Inductance in henries and capacitance in farads (inputs are converted from mH and µF).
Worked examples
This example is verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Inductance = 1; Capacitance = 1.
| Result | Value |
|---|---|
| Resonant frequency | 5,032.9212 Hz |
The first line is the headline result (resonant frequency). IEEE-754 double precision; shown to at most 6 decimal places.
At resonance
At f₀ the inductive and capacitive reactances are equal and cancel, so a series circuit has minimal impedance and a parallel one has maximum impedance. This is how radios tune to a station.
Ideal components
The formula ignores resistance and parasitics. Real circuits resonate slightly lower and with damping, described by the Q factor. To halve the frequency, quadruple L or C.
How the result changes with inductance
Holding every other input at the first worked example, this table changes only inductance. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Inductance | Resonant frequency |
|---|---|
| 0.5 | 7,117.6254 Hz |
| 1 | 5,032.9212 Hz |
| 2 | 3,558.8127 Hz |
| 4 | 2,516.4606 Hz |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Inductance: entering "0" shows "Inductance must be greater than 0." beside that field and no result.
Choosing between the LC Resonant Frequency Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Ohm's Law Calculator](/engineering/ohm-s-law-calculator/) | Current | |
| [Parallel Resistor Calculator](/engineering/parallel-resistor-calculator/) | resistances | Parallel resistance |
| [Watt-Hours Calculator](/engineering/watt-hours/) | use | Energy |
| [Wattage Calculator](/engineering/wattage/) | Power | |
| [Battery Runtime Calculator](/engineering/battery-runtime-calculator/) | battery capacity, battery voltage and load | Runtime |
Background: electrical circuits
Ohm's law links voltage, current and resistance: V = I × R, so I = V ÷ R and R = V ÷ I. Power is P = V × I, which also equals I² × R and V² ÷ R.
These relations hold for ohmic components, where resistance is constant. Diodes and transistors are non-linear, and in AC circuits with reactive parts impedance (Z) takes the place of resistance. Check component ratings and local electrical code before relying on any calculation.
Assumptions and limitations
- Ideal components
Use results as engineering estimates and check them against the governing standards, safety factors and a qualified engineer's judgement before relying on them.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for inductance to confirm this.
Frequently asked questions
How do I raise resonant frequency?
Reduce L or C, because f = 1 ÷ (2π√(LC)); quartering either one doubles the frequency.
What is Q?
A measure of how sharp the resonance is.
Is it the same for series and parallel?
The frequency is the same.
What does the LC Resonant Frequency Calculator calculate?
Resonant frequency of an LC circuit. It returns Resonant frequency.
What formula does the LC Resonant Frequency Calculator use?
f = 1 ÷ (2π√(LC)). Inductance in henries and capacitance in farads (inputs are converted from mH and µF).
What do I need to enter in the lC Resonant Frequency Calculator?
You enter Inductance (mH) and Capacitance (µF).
How is the result rounded or limited?
IEEE-754 double precision; shown to at most 6 decimal places. Ideal components.
What is an example of a lC Resonant Frequency result?
With inductance 1 and capacitance 1, the resonant frequency is 5,032.9212 Hz.
Can I rely on this calculator for a decision?
Use results as engineering estimates and check them against the governing standards, safety factors and a qualified engineer's judgement before relying on them. For this calculator in particular: Ideal components.
Related calculators
- Ohm's Law Calculator — Solve voltage, current or resistance.
- Parallel Resistor Calculator — Equivalent resistance of resistors in parallel and in series.
- Watt-Hours Calculator — Energy in watt-hours from power and time, or from amp-hours and voltage.
- Wattage Calculator — Solve power, voltage or current for a DC or resistive load.
- Battery Runtime Calculator — Runtime of a battery under a constant load.
- Frequency Converter — Convert hertz, kilohertz, megahertz, gigahertz and rpm.
Sources
- OpenStax, University Physics Volume 1 (Rice University): mechanics
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.