About this tool
LC Resonant Frequency Calculator is a free, in-browser tool for tuned LC circuits. Pick which quantity to solve for — resonant frequency, inductance or capacitance — and it returns the missing value. All math runs locally in your browser.
The resonant frequency of an LC tank is f = 1 / (2π·√(L·C)). Rearranged, the inductance for a target frequency is L = 1 / ((2π·f)²·C) and the capacitance is C = 1 / ((2π·f)²·L). At resonance the inductive and capacitive reactances are equal, X = 2π·f·L = 1/(2π·f·C), which the tool also reports. Inductance accepts H/mH/µH, capacitance accepts pF/nF/µF and frequency accepts Hz/kHz/MHz through the unit selectors, and results are auto-scaled for readability.
Use it to design a radio tuner, oscillator tank, or filter: enter two of the three quantities and read off the third. The reactance tile helps you match the tank to the surrounding impedance.