Find any piano chord or scale in seconds — even when you don't know its name. Piano Companion is the music theory app trusted by over 1,000,000 musicians worldwide, rated 4.75★ from 22,000+ reviews.

Forget what a chord is called? Press a few keys on the on-screen piano or your MIDI keyboard and the app identifies it instantly. Looking for a scale that fits a song you're writing? The interactive Circle of Fifths shows every compatible chord at a glance.

What you can do with Piano Companion

- Look up 1500+ piano chords up to the 6th inversion — major, minor, diminished, augmented, sevenths, and beyond.
- Browse 10,000+ scales — major, minor, chromatic, pentatonic, blues, modes, and more.
- Build harmonies in the Chord Progression Builder using relative or common chords.
- Hear how a chord or scale sounds in loop or arpeggio.
- View notes on the staff in treble and bass clef.
- See fingerings for both hands in major and minor scales — and contribute your own.
- Connect an external MIDI keyboard to play and search in reverse mode.
- Send MIDI output to your favorite DAW.
- Switch between English, Italian, German, Japanese, Russian, and other key notations.
- Save your own libraries, favorite scales, and custom chord charts.
- Songbook: write lead-sheet songs with lyrics and chords, play them back with auto-scroll, and export to PDF.

Built for music theory learning

Piano Companion teaches music theory through hands-on practice. The app labels secondary dominants, leading tones, and common degrees — Tonic, Supertonic, Mediant, Subdominant, Dominant, Submediant, Leading tone (in major) and Subtonic (in natural minor) — so you can study how progressions are built. Listen to relative scales side by side, browse compatible chord-and-scale pairings, and try modes you've never used.

Songwriting and composition

Use the chord wheel and progression sequencer to compose songs from scratch. Add arpeggios, swap chords for relatives, and play the result on the built-in piano or through MIDI.

Questions or suggestions? Email support@songtive.com or visit forums.songtive.com.

Download free and start exploring music theory today.