Crossover Calculator
Work out the capacitor and inductor values needed to build a simple passive speaker crossover at your chosen frequency.
What a crossover calculator does
A passive speaker crossover splits an audio signal between drivers (for example a woofer and a tweeter) so each one only receives the frequency range it handles well. This is done with a low-pass inductor feeding the woofer and a high-pass capacitor feeding the tweeter.
The formulas used
For a simple first-order (6 dB/octave) filter at impedance Z and crossover frequency f, the inductor value is L = Z / (2πf) and the capacitor value is C = 1 / (2πfZ). A second-order Butterworth filter scales both values by √2 for a steeper, flatter-response rolloff.
- Higher impedance drivers need larger inductor and smaller capacitor values.
- Real drivers are not purely resistive, so treat these as a solid starting point rather than a final, measured design.
This tool is for general electronics planning and education, not a substitute for measured, driver-specific crossover design.