LC Resonant Frequency Calculator
Enter the known values and run the calculation.
Calculate resonant frequency from known inductance and capacitance.
Pick whether you want to solve for frequency, inductance, or capacitance.
Enter the known values, choose the engineering units that match the parts on your bench, and run the calculation. The result card reports the solved value plus resonance-adjacent context such as period, angular frequency, and reactance.
Overview
Calculate the natural resonant frequency of an LC network for tuning and filter work.
This tool solves the ideal resonance relationship for an LC network without making you convert units by hand every time.
Use it for tuned filters, oscillators, matching-network work, and first-pass design checks when you need to move quickly between frequency targets and practical L/C values.
The math and how it's used
Rearranged for inductance: L = 1 / (((2 * pi * f)^2) * C).
Rearranged for capacitance: C = 1 / (((2 * pi * f)^2) * L).
These relationships assume an ideal, lossless LC network. Real ESR, winding resistance, and parasitics will move the measured resonance.
Under the hood, this is the standard ideal LC resonance relationship. It is the first number engineers reach for when picking starting values for tuned filters, oscillators, and matching experiments.
Once the design moves off the whiteboard, winding resistance, capacitor ESR, layout parasitics, and loading from the next stage can all pull the measured resonance away from the textbook result.
What to watch
This is the ideal textbook relationship. Real circuits shift because of coil resistance, capacitor ESR, parasitic capacitance, stray inductance, loading from the next stage, and measurement fixture effects.
Use this as the fast planning number, then verify the real circuit with a scope, network measurement, or impedance measurement setup if the target is tight.