Best music theory apps and books for classical pianists
musictheory.net is free, Tenuto is $4.99, and the chord names are in the E minor prelude.
musictheory.net is free, Tenuto is the same 24 exercises for $4.99, and Open Music Theory is a free textbook. The chord names in those drills are printed on the E minor prelude and on Op. 9 No. 2.
Drill apps
musictheory.net and Tenuto
The site is free, with lessons from the staff up to chord progressions and Neapolitan chords, and exercises that ask you to name or build notes, intervals, scales and chords on a staff or a keyboard, plus ear training. Tenuto is the same 24 exercises as a $4.99 iPhone and iPad app with a timed challenge mode.
Teoria
Free and run on donations for 29 years, with tutorials on intervals, scales, chords, harmonic functions and musical form, and exercises that include harmonic progressions, harmonic analysis and four-voice dictation.
Hooktheory
Hookpad is a chord-and-melody sketchpad with a free tier, then $7.99 a month or $199 for life, and TheoryTab is its database of more than 80,000 songs analyzed in roman numerals. The $14.99 Hooktheory I book teaches harmony from those songs in a relative notation that needs no staff reading. The examples are Taylor Swift, The Beatles, Lady Gaga, and Bruno Mars.
Perfect Ear
Free on iPhone, iPad, Mac and Android, with $4.99 for the full exercise pack or $14.99 for Premium. It drills intervals, chords with inversions and progressions, scales, rhythm, melodic dictation and sight reading.
Functional Ear Trainer
Free desktop software since 2002 and a free phone app with a $19.99 Plus upgrade. It plays a cadence to set the key, then one note, and you name its scale degree, which is Alain Benbassat’s method. It trains single notes and pairs of notes.
ToneGym
A free plan, then Pro at $13.95 a month or $204 for life, with 17 games covering intervals, chords, progressions, scales, rhythm, melodic dictation and sight-reading in a daily workout of 10 to 15 minutes.
Books
Open Music Theory
Free online and as a PDF under CC BY-SA, version 2 from 2023 by Mark Gotham and six co-authors. It covers fundamentals, diatonic and chromatic harmony, form, jazz and pop, with a complete workbook of assignments. This is the reference to keep open when a chord in a score has a name you do not know.
Tonal Harmony
Kostka and Payne’s standard text, now Kostka and Almén in the 9th edition of 2024: $261.99 in print or $65.99 as a 180-day eBook from McGraw Hill, 28 chapters from fundamentals to post-tonal music, a two-year college sequence.
The Complete Musician
Laitz and Callahan, fifth edition, Oxford, $147.99 at the Juilliard Store. It teaches theory in the context of performance.
Harmony at the Piano
Ken Johansen, Routledge, 2024, paperback around $70 to $85 depending on the seller. Written for pianists: chord progressions, figured bass, melody harmonization, reduction and repertoire study, played at the keyboard. It assumes you already play advanced repertoire.
In the pieces you play
In Chopin every bar is a chord you can name and play. In a Chopin Left Hand edition every chord is named above the staff (B, F♯⁷, C♯m, E♯°⁷) and numbered below (I, V⁷, vii°⁷/V, Ger⁺⁶), the right hand is exactly as Chopin wrote it, and the left hand is one plain root-position chord per harmony, so you can play the whole progression through as slowly as you need to hear it. Boxed section letters mark the form, and the analysis page explains the notable chords: what the German sixth is doing in bar 23 of the E minor prelude, why the cadenza of Op. 9 No. 2 sits on one chord, B♭⁷, before E♭ arrives.
Bar 1 of Op. 9 No. 2 has D°⁷ on the second beat, named above the staff.
Buy one Chopin Left Hand edition, $9: every chord in the nocturne named above the staff and numbered below, under Chopin’s melody.
Drill the names for free beside it with musictheory.net (Tenuto on iPhone and iPad, $4.99), keep Open Music Theory open as the free reference, and add Functional Ear Trainer, free, for scale degrees. The whole path costs under $15.
The E minor prelude, then Op. 9 No. 2
The E minor prelude, Op. 28 No. 4, is the classic first harmonic analysis: 25 bars, Largo, a left hand that sinks by half steps under a melody that barely moves, and a deceptive cadence and a German sixth in the last five bars, all named on a 2-page PDF. Then Op. 9 No. 2, 34 bars in which the theme returns over nearly the same chords each time, so you learn one progression and hear it four ways. The bar-by-bar analysis of the prelude is free in Prelude in E minor, Op. 28 No. 4: chords and analysis, the apps that grade your playing are in best piano apps for intermediate adults, and the books and courses around them are in best piano learning resources for intermediate players.