Calculate the quality factor of a resonant circuit and the selectivity it provides.
Q can be measured from the response shape or predicted from component values, and the two should agree. It expresses how much energy is stored relative to that lost each cycle, which is why low resistance gives high Q. High Q means sharp selectivity but also long ringing, so filter and antenna design always trades the two against each other.
Q Factor
Q = f₀ ÷ bandwidth = 2πf₀L ÷ R
Q = f₀ ÷ bandwidth = 2πf₀L ÷ R Q can be measured from the response shape or predicted from component values, and the two should agree. It expresses how much energy is stored relative to that lost each cycle, which is why low resistance gives high Q.
High Q means sharp selectivity but also long ringing, so filter and antenna design always trades the two against each other.
This calculator takes 4 inputs: Resonant frequency, Measured bandwidth, Series resistance, Inductance. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.