HearmonyMusic Theory Basics: What to Learn and in What Order
Music theory basics come in a natural order: notes, then rhythm, then intervals, scales, keys, chords and finally chord progressions. Each step is built from the one before it, so a major scale is just a pattern of intervals, a chord is notes stacked from a scale, and a progression is chords moving inside a key. Learn the steps in that order, and listen to every new idea as well as reading about it.
What is music theory?
Music theory is the shared vocabulary musicians use to describe how music works: what the notes are called, how long they last, and how they combine into scales, chords and keys. It describes what composers and players already do; it is not a set of rules you must obey.
For a beginner, theory answers practical questions. Why does a song sound finished on one chord and unfinished on another? Why does C–E–G sound bright and C–E♭–G sound darker? Which notes can you play over a song without clashing? The wider field of music theory also covers history, acoustics and analysis, but the basics below are what most players and singers actually use.
The learning order at a glance
Seven steps cover the basics. The table shows what to learn at each one and a simple check that you are ready to move on.
| Step | Learn | Example in C | You're ready to move on when |
|---|---|---|---|
| 1. Notes | Letter names, sharps and flats, octaves, the staff | C D E F G A B, plus C♯/D♭ and the other black keys | You can name any key on a keyboard and any note on the treble staff |
| 2. Rhythm | Beat, note values, rests, time signatures | Four quarter notes fill a bar of 4/4 | You can clap a written line of quarters, halves and eighths |
| 3. Intervals | Half and whole steps, interval names | C–E is a major third, C–E♭ a minor third | You can count the half steps in any interval up to the octave |
| 4. Scales | Major and natural minor patterns | C major: C D E F G A B C | You can build a major scale from any note |
| 5. Keys | Key signatures, relative minor, circle of fifths | G major has one sharp (F♯) | You can name the key from a signature |
| 6. Chords | Triads, then seventh chords and inversions | C major C–E–G, C minor C–E♭–G | You can spell the major and minor triad on any root |
| 7. Progressions | Roman numerals, common progressions, cadences | I–IV–V–I = C–F–G–C | You can write the chords of a key and label a simple song |
Steps 1 and 2: notes and rhythm
Notes and rhythm come first because everything else is described with them. Western music uses 12 different notes, repeating in every octave: seven letter names (A to G) on the white keys of a piano, and five black keys named as sharps or flats of their neighbors.
- Half step: the distance from one key to the very next, black or white (E–F, B–C, C–C♯).
- Sharp and flat: ♯ raises a note a half step, ♭ lowers it. C♯ and D♭ are the same key with two names; which name you use depends on the key you are in.
- The staff: five lines on which notes are written. The treble clef covers higher notes, the bass clef lower ones.
Rhythm is the time side: a steady beat, notes that last a number of beats, and a time signature that groups beats into bars. In 4/4, a whole note lasts four beats, a half note two, a quarter note one and an eighth note half a beat. Our guide on how to read sheet music puts the staff, clefs and rhythm together, and the page on note values has the full table of notes and rests.
Steps 3 to 5: intervals, scales and keys
Intervals, scales and keys are one idea at three sizes: an interval is the distance between two notes, a scale is a fixed pattern of those distances, and a key is a scale used as home.
Intervals
Count intervals in half steps. Two half steps make a whole step (C–D); three make a minor third (C–E♭); four a major third (C–E); seven a perfect fifth (C–G); twelve an octave (C–C). Learning each interval with a song you know turns the numbers into sounds; our interval song chart lists one for every interval.
Scales
The major scale follows the pattern whole–whole–half–whole–whole–whole–half. From C that gives C D E F G A B C, all white keys. From G it gives G A B C D E F♯ G, so the seventh note needs a sharp. The major scale guide builds it from all 12 notes. The natural minor scale uses whole–half–whole–whole–half–whole–whole: A B C D E F G A.
Keys
A key is a scale treated as home, and the key signature at the start of each staff tells you which sharps or flats that scale needs. G major has one sharp (F♯), D major two (F♯, C♯), F major one flat (B♭). Each major key shares its signature with a relative minor: C major and A minor both have no sharps or flats. The page on key signatures gives the full table and the tricks for reading them.
Steps 6 and 7: chords and progressions
Chords are notes from the scale stacked in thirds, and progressions are chords moving through a key. This is where theory starts to explain the songs you hear.
A triad has three notes: a root, a third and a fifth. Change the thirds and you change the color:
| Triad | Built from | On C | Sound |
|---|---|---|---|
| Major | Major third + minor third | C–E–G | Bright, stable |
| Minor | Minor third + major third | C–E♭–G | Darker, softer |
| Diminished | Two minor thirds | C–E♭–G♭ | Tense, unstable |
| Augmented | Two major thirds | C–E–G♯ | Unresolved, dreamy |
Build a triad on every note of C major and you get the chords of the key: C, Dm, Em, F, G, Am and B°. Theory labels them with Roman numerals, I ii iii IV V vi vii°, uppercase for major and lowercase for minor. The guide to triads goes through all four qualities in more keys.
Numerals let you describe a progression in any key at once. I–IV–V–I is C–F–G–C in C major and G–C–D–G in G major, and it sounds like the same move in both. The most common chord progressions are a short list, and learning them is the payoff for the six steps before.
Learn theory with your ears, not only on paper
Theory sticks when every term has a sound attached. Knowing that C–E♭ is a minor third is useful; hearing a minor third and naming it is what helps you play by ear, sing in tune and work out songs.
A simple routine pairs each step with a listening task. Spend about 15 minutes on the concept and 10 on hearing it.
| Week | Theory | Ear task |
|---|---|---|
| 1 | Note names, half and whole steps | Is the second note higher or lower? Same or different? |
| 2 | Note values, 3/4 and 4/4 | Clap along to songs; count whether the bar has 3 or 4 beats |
| 3 | Intervals up to the octave | Name thirds, fourths, fifths and octaves with song anchors |
| 4 | Major and natural minor scales | Sing do–re–mi; hear whether a melody is major or minor |
| 5 | Key signatures | Hum the home note of three songs |
| 6 | Triads | Major or minor? Then add diminished and augmented |
| 7 | I, IV, V, vi and cadences | Hear I–IV–V–I against I–V–vi–IV |
The listening column follows the same order as the ear training for beginners plan, so you can run both side by side. Some weeks will take longer; move on when the check in the first table is easy, not when the calendar says so.
Common mistakes when learning music theory
Most beginners stall for the same few reasons, and each has a simple fix.
- Jumping straight to chords. Chords are spelled from intervals and scales. If triads feel like memorization, go back to step 3 and count half steps.
- Spelling with the wrong letter. A minor third above C is E♭, not D♯, even though both are the same key. Each scale uses each letter once, so F major has B♭, never A♯.
- Learning only in C. C major hides sharps and flats. Repeat every step in G and F, then in D and B♭.
- Reading without listening. Play every example, even with one finger. A term you have heard is a term you remember.
- Skipping rhythm. Many people learn pitch first and leave rhythm for later. Counting is half of reading music and most of playing with others.
Follow the same order in Hearmony
Hearmony is an ear-training app for iPhone, and its path of 12 adventures follows roughly the order above on the listening side. First Notes starts with higher, lower, same and different; Leap Lagoon and later Interval Peaks cover intervals; Chord Garden trains major, minor, diminished and augmented chords; Rhythm Ranch handles beat, meter and syncopation; Home Key Harbor teaches scale degrees in solfège; Progression Highway covers I–IV–V, the pop progression, ii–V–I and cadences; Seventh Heaven adds seventh chords and inversions.
Two side quests are always free and cover the reading side: Note Reading (notes on the staff, lines and spaces, finding keys) and Chord Numbers (what I, IV, V and vi mean). Lessons are 10 questions, so one fits into the ear-task half of the weekly routine. Hearmony is on the App Store.