Music theory, scales, chords, ear training & songwriting tool for all musicians
4.42·2,399 reviews·500,000+ downloads
Music Theory Companion is a comprehensive all-in-one toolbox for musicians, merging scales, chords, ear training, and songwriting into a single app. It pairs theory with practical practice tools like a realistic piano keyboard, guitar fretboard, metronome, and voice-leading guidance to support musicians from beginners to seasoned composers.
Pros & Cons
Comprehensive, all-in-one toolbox for theory and practice (scales, chords, intervals, voice leading, modulation)
Large chord library of 1000+ chords with construction details and a finder tool
Cross-instrument support (piano, guitar, voice) with realistic keyboard and fretboard visuals
Practical practice tools (metronome, pitch detector, staff view, online theory resources) and ongoing updates
Some resources are online-only (Music Theory Reference) rather than offline
No explicit MIDI export or built-in song library indicated in the data
Not ranked in any top app lists, which may affect visibility compared to competitors
About Music Theory Companion
Music Theory Companion is a music & audio app developed by PG App Studio.
How many times has Music Theory Companion been downloaded?
Music Theory Companion has been downloaded 670 thousand times. In the last 30 days, the app was downloaded 12 thousand times.
What is the rating of Music Theory Companion?
Music Theory Companion is rated 4.42 out of 5 stars, based on 2.4 thousand ratings.
Is Music Theory Companion free?
Music Theory Companion is free to download. The APK download size is 14.41 MB. The latest version available is 8.2.3. The last update was on June 30, 2026.
What are the requirements for Music Theory Companion?
Music Theory Companion requires Android 7.0+ or higher. The app has a content rating of Everyone. The app has been available on Google Play July 2018.
Description
Unlock your musical potential with the Music Theory Companion app! This comprehensive tool is designed for musicians of all levels, from beginners to experienced composers. Whether you're into songwriting, music theory study, or want to improve your playing, this app is a goldmine. This app helps you develop your aural skills and relative pitch. It can help with improvisation, composition, arrangement, and interpretation.
🌟 KEY FEATURES: ✅ Scales & Chords: Explore 86 unique heptatonic scales/modes and their diatonic triads/seventh-chord formations. The app has a wide list of scales for guitar, piano and vocal. ✅ Matching Chords: Discover alternative chords for any note in any scale. ✅ Matching Scales: Find alternative scales that can be played with any given scale. ✅ Circle of Fifths: Visualize the circle of fifths for all 86 scales, with options for triads and seventh chords. The circle of fifths tool can be used for finding chord progressions. The app supports both clockwise and anticlockwise directions for the circle of fifths. ✅ Voice Leading: Use the Cube Dance tool for voice leading guidance based on Neo-Riemannian theory. ✅ Chord Library Access a library of 1000+ chords, with chord construction details. This can be used as a chord finder. ✅ Modulations: Explore various chord progression options for smooth key changes. ✅ Scale Practice: Use the pitch detector to practice scales on guitar, piano, or vocals. This app can also be used for vocal training and helps with ear tuning. ✅ Intervals: Train your ear with interval exercises in all keys. ✅ Metronome: Practice with a highly accurate metronome that has configurable sounds. The metronome can be used with guitar, drum set, piano, and vocal practices. ✅ Piano: A realistic piano keyboard with different instrument sounds. This can be used as a piano chords learning app. ✅ Guitar Fretboard: Realistic left-handed and right-handed guitar fretboard display. The app is also a guitar chords app. ✅ Musical Symbols: Quick online reference for musical symbols. ✅ Music Theory Reference: Access a vast collection of online music theory resources, making it a great free music theory book. ✅ Supports both sharp (#) and flat (b) notes for root. ✅ Play guitar chords or piano chords in sync with the metronome ticks. ✅ Has a simple and easy-to-use user interface. ✅ Provides analytical labels such as Secondary Dominant and Secondary Leading-Tone. ✅ Shows compatible scales' chords. ✅ Displays similar and relative scales. ✅ Shows common degrees: Tonic, Supertonic, Mediant, Subdominant, Dominant, Submediant, Leading tone (in Major scale) / Subtonic (in Natural Minor Scale) ✅ Displays compatible chords' scales. ✅ Shows chords and scales on the staff with treble and bass clef.
🎯 APP USAGE: This app is a complete toolbox for musicians and can be used for: ✅ Music Composing ✅ Music Theory Study ✅ Chord Progressions ✅ Modulation and Key Change ✅ Voice Leading ✅ Guitar and Piano Chord Practice ✅ Vocal Training ✅ Ear Training ✅ Sight reading
🎼 Designed for: 🎹 Pianists & keyboard players 🎶 Musicians, composers, and songwriters 🧠 Music theory learners & teachers 🎓 Students preparing for music exams 🎧 Anyone who loves creating music
The Music Theory Companion app has a realistic piano keyboard and guitar fretboard. It also has a pitch detector. This app is continuously updated and improved.
COMMUNITY
Follow us on Facebook https://www.facebook.com/MusicCompanionApp/
Join Our Facebook Group https://www.facebook.com/groups/MusicCompanionGroup/
Recent changes: ✓ Increased the interval before showing the first full-screen ad ✓ Enhanced chord playback in piano Chord Pad ✓ Improved pitch detection ✓ Improved piano user interface
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Love this app!! Helped me learn how to sight-read along with learning songs!! There are a few ads, but they are not as annoying as people make them out to be. The best thing about this is that it's free and available on Android unlike Pocket Pitch or other helpful music tools. It can also be a bit complicated for guitar chords, as it shows every possible finger placement for that chord, but I mostly use it for piano and choral pieces anyway.
★★★★★Eric Hartman· Nov 27, 2025
Worth so much more than any other music app I've ever used. I basically learned Theory entirely from this app.
★★★★★Chris Nusbaum· Mar 2, 2025
Great app! It's so useful to have a collection of tools like this in one place. I really like the ability to flip between viewing notes/chords on a staff, piano, and guitar fretboard. And as a lefty, being able to flip the guitar fretboard around is super helpful. One thing that would make it even better is to somehow integrate chord inversions and different chord voicing, w/ ability to hear & see them visually represented on staff/piano/fretboard. I'll add a plus to my 5* for that 😄.
★★☆☆☆John Pampliega· Sep 6, 2025
Hello. I'm not too sure if I'm using the app correctly, but it seems that I can't hear any sounds play at all. The only time I hear something is when I go through the playback of the grand piano feature. Because of it, the entire app experience, for me, was lost. This might be a bug or a performance issue. I want to give this app a second chance, because it does look pretty promising to use.
★☆☆☆☆Mark Automaton· Jun 10, 2025
Used to use this all the time, but now the intrusive full screen ads have taken over, making it unusable. Uninstalled.
★☆☆☆☆Vince Paul· Apr 16, 2025
I don't get it. Tried the "modulation" but it doesn't have progressions, it just repeats the last chord you selected. No target chord, no way to select "a progression"... on second thought I'm lowering my rating. I don't know why I gave it so many stars in the first place.
★☆☆☆☆Robin Svoboda· Sep 26, 2025
It might be good but the aggressive coomer ads they have just makes this hot garbage and nothing else. I installed it and wanted to check how much the premium version was and the moment I opened the settings I was met by one enforced coomer ad, not to mention the banner one which is there always and acceptable. They also sell your data even if you buy premium so this just hot and marinated garbage on fire.
Google Play Rankings for Music Theory Companion
This app is not ranked
Technologies used by Music Theory Companion
15 permissions·20 libraries
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Trust & Safety: The app requests microphone access (RECORD_AUDIO) for pitch detection, along with Internet, network state, foreground service, notifications, and Google/Ad ID related permissions. In-app billing is present, and there are dynamic/broadcast-related permissions noted. This combination aligns with its features (pitch detection, online resources, ads, and background tasks). The FOREGROUND_SERVICE and advertising-related permissions suggest background operation and monetization, while the RECORD_AUDIO permission is necessary for its core ear-training capabilities. Overall, permissions appear typical for an audio-focused learning app, with standard safety considerations for advertising and user data use.
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