LC Filter Cutoff Frequency Calculator

Find the cutoff frequency of your LC filter.

Values

Filter type

Inductance L (µH) Capacitance C (nF)

Result

f_c = 1.59 kHz

Passive filter cutoff

First-order RC/RL and LC filters roll off at −20 dB/decade after their cutoff frequency: f_c(LC) = 1 / (2π√(LC)), f_c(RC) = 1 / (2πRC), f_c(RL) = R / (2πL).

At f_c the output is −3 dB relative to passband. Use LC for power filtering (higher efficiency) and RC where component count and cost matter.