Cartridge Loading Calculator
Moving-magnet cartridges are sensitive to capacitance. Your tonearm's wiring and cable add some, your phono stage adds some more, and the total affects how the treble behaves, so most makers publish a recommended range. This adds up what your system has and checks that the total lands inside it.
The calculation assumes the standard 47 kΩ moving-magnet input, and it covers the electrical behaviour only. A cartridge's mechanical design is tuned on the assumption that it sees the recommended load, which is why staying inside the range matters more than chasing any single figure. Moving-coil cartridges barely react to capacitance, so this calculator is for moving-magnet and moving-iron types. If you don't know your phono stage's input capacitance, its manual usually lists it.
Check the mechanical match too with the resonance calculator →
Who makes these
Bool Audio is a father and son making hi-fi components in a small UK workshop. We build the Clear Wave unipivot tonearm and the Clear Wave 2.0 tonearm cable, both for the Linn LP12. These calculators began as our own bench arithmetic. They are free to use, there is nothing to install, and they take no view on which cartridge or tonearm you should own.