Frequently Asked Questions

Questions, Answered

What does the calculator count as a step?

The distance one voice travels from its note in the first chord to its partner in the second, in semitones, measured the shorter way round the octave. C to E is four semitones; B to C is one; C to A is three, downward, not nine upward. A voice that stays on the same note is a common tone and costs nothing.

Why pitch classes, with no key and no instrument?

Because the shortest way between two chords does not depend on either. C major to A minor leads exactly as D major to B minor does, one key higher, and the distances are the same whether the voices are sung, bowed or played on a keyboard. Working in pitch classes keeps one answer per pair of chord types instead of twelve copies of it.

How does it pair the voices?

One to one. Every voice of the first chord is matched with exactly one voice of the second, every possible matching is tried, and the matching whose steps add up to the fewest semitones comes first. Two voices are never allowed to lead from the same note, which is the shortcut a greedy pick takes.

What happens when two leads tie?

Both are shown. A tie is part of the answer: it means the voices have more than one equally short path, and choosing between them is a matter of register or taste, not distance.

Can it lead a triad into a seventh chord?

Not yet. The calculator pairs two chords only when they hold the same number of notes. A triad and a seventh chord would need one voice to split in two, or two voices to merge into one, and rather than pick a rule for that it refuses the pair and says why.

Why is there no page for each chord?

Because the network already has them: the instrument sites publish every chord on their own necks and keys. This site keeps to the distance between two chords, and a pair of chord symbols is read in your browser rather than given an address of its own.