PureTune Keys

Compare equal temperament and just intonation as you play. Root C is free; unlock all 12 keys permanently with Pro.

PureTune Keys is a keyboard for playing and comparing equal temperament and just intonation. Hear the difference in intervals and chords directly on the on-screen keyboard. A supported wired USB MIDI keyboard can also be used.

FEATURES • Switch between equal temperament and just intonation • Choose major or minor • Select a root key • Adjust the waveform, master pitch, and volume • Sustain notes after releasing the keys • Shift the keyboard octave • See active notes and tuning offsets • Stop every note instantly with the Off button

The free version includes Root C. A one-time Pro purchase permanently unlocks the other 11 root keys. This is not a subscription.

MIDI hardware is optional. Every feature can be reviewed with the on-screen keyboard.