Theory Lessons
by musictheory.net
- Music
- Paid
- Small & simple · 93
- Rating
- 4.4
- 126 ratings · US storefront
- Top 96%among 82 Music apps
- Last update
- Apr 21, 2026
- Version 3.2.1
- Size
- 5 MB
- Category
- Music
- Tracked since
- Oct 9, 2026
Estimated revenue
A model estimate with a likely range, not a reported figure.
No estimate. Apps outside the grossing charts, and some countries, have no reliable rank-to-revenue curve, so we show nothing rather than a guess.
How this estimate is made
Rank: we take the app's best Top Grossing rank on the latest chart day. Category ranks are converted into an equivalent overall rank, because a #10 in Finance earns far less than a #10 overall.
Curve: that equivalent rank is read off a rank-to-revenue curve anchored on public company revenue and market-data reports for the US iPhone App Store.
Country: the curve is scaled per country (Japan is roughly a third of the US, Türkiye under 1%). Where we have no scale, such as China, there is no estimate.
Range: the likely range widens with country, category and chart depth. It is a plausible span, not a statistical confidence interval.
Not included: ads, payments outside the App Store, and any difference between gross sales and what the developer keeps. Low confidence means indirect data; medium means several independent sources agree.
Full methodScreenshots
As shown on the App Store listing.
About this app
Text from the App Store listing.
Theory Lessons features 39 music theory lessons from musictheory.net, presented in their original animated versions.
Complete lesson list:
- The Staff, Clefs, and Ledger Lines
- Note Duration
- Measures and Time Signature
- Rest Duration
- Dots and Ties
- Steps and Accidentals
- Simple and Compound Meter
- Odd Meter
- The Major Scale
- The Minor Scales
- Scale Degrees
- Key Signatures
- Key Signature Calculation
- Generic Intervals
- Specific Intervals
- Writing Intervals
- Interval Inversion
- Introduction to Chords
- Triad Inversion
- Seventh Chords
- More Seventh Chords
- Seventh Chord Inversion
- Diatonic Triads
- Roman Numeral Analysis: Triads
- Diatonic Seventh Chords
- Roman Numeral Analysis: Seventh Chords
- Composing with Minor Scales
- Voicing Chords
- Analysis: O Canada
- Nonharmonic Tones
- Phrases and Cadences
- Circle Progressions
- Common Chord Progressions
- Triads in First Inversion
- Triads in Second Inversion
- Analysis: Auld Lang Syne
- Building Neapolitan Chords
- Using Neapolitan Chords
- Analysis: Moonlight Sonata
What’s new
Release notes for the latest version, as written by the developer.
- Fixes an issue where opening a link to a lesson could fail.
- Updates the app icon used in Dark, Clear, or Tinted modes.
- Fixes an issue where the wrong image would show in "The Staff, Clefs, and Ledger Lines".
- Corrects typographical errors in "The Minor Scales", "Diatonic Seventh Chords", and "Roman Numeral Analysis: Seventh Chords".
Rank history
Daily position in the Dominica charts. #1 is at the top.
- Best rank
- #4
- Current rank
- #4
- Days charting
- 7 of 7
On the charts today
Small & simple score
How realistic it is for a small team to build something like this.
93/100
Small & simple
- Developer size70% · 25
Developer: 2 apps on the charts
- Audience size100% · 20
Ratings: 126
- App size100% · 10
Size: 5 MB
- Price model100% · 15
Price model: paid
- Demand proof100% · 30
Best rank #1, 130 countries
An indicator, not a fact. We can't see team size. Calculated Oct 24, 2026 · method i2
How the score worksVersion history
- 3.2.1LatestReleased Apr 21, 2026