How do quarter-tone keyboards differ from standard 12-note keyboards?

Standard 12-note keyboards are designed for equal temperament, a system that divides the octave into 12 semitones of equal size. This configuration allows instruments to play in all musical keys with consistent, though slightly imperfect, intonation.12

In contrast, keyboards designed for quarter-tone intervals divide the octave into 24 equal parts rather than 12. While standard keyboards rely on the 12-note chromatic scale, quarter-tone instruments provide a more granular division of the octave to accommodate microtonal music that utilizes intervals smaller than a semitone.3

Historically, some keyboards featured "divided sharps" to address the limitations of meantone temperament, where keys like E♭ and D♯ could not be used interchangeably without retuning. While these split keys allowed for more refined tuning by providing separate surfaces for enharmonic equivalents, they differ from modern quarter-tone keyboards, which are specifically engineered to facilitate the playing of 24-tone equal temperament.32