Chord Progression Ear Trainer
A short progression plays in a random key every round. Name what you hear in roman numerals — function, not letters.
The idea
Each round picks a progression and a random key, then plays it. Because the key changes every round you cannot memorise "that was a G chord" — you have to hear the function of each chord relative to the tonic. The tonic reference chord that plays first is your anchor: hold it in your head and measure everything against it.
Reading the numerals
- Case carries the quality. UPPERCASE = major triad (I IV V, and III VI VII in minor). lowercase = minor triad (ii iii vi, and i iv v in minor).
- ° means diminished — vii° in a major key, ii° in a minor key. Always lowercase, because a diminished triad has a minor third.
- Major key, chords built on scale degrees 1–7: I ii iii IV V vi vii°.
- Natural minor: i ii° III iv v VI VII. The extra V button is the harmonic-minor version — a major chord on degree 5, the one that pulls hardest back to i. Both v and V are offered, and they sound clearly different.
Mouse and touch
- Play progression sounds the round (and replays it as often as you like). Tonic reference re-sounds just the tonic chord. New round skips to a fresh progression and key.
- Tap a roman numeral to drop it into the next empty answer slot. Tap a filled slot to empty just that one — handy when you only want to change the third chord.
- Undo removes the last numeral you placed, Clear empties every slot.
- Submit marks each slot on its own: a slot you got right shows a check and the word right; a wrong one shows a cross, strikes out your guess and prints the correct numeral underneath.
- Reveal gives up on the round and shows the answer — it counts as an attempt, so your score stays honest.
- Play-along walks the progression one chord at a time, lighting up the numeral in your answer row and the matching button, and printing the real chord name in this round's key (for example V = D in G major). That link between numeral, sound and letter is the whole point.
- Progression length restricts the pool to 3-chord or 4-chord progressions; As written also allows the longer ones (the Pachelbel canon is eight chords, the blues is six).
- Difficulty pool: common pop progressions, plus optional jazz ii–V–I family and optional minor keys. At least one pool always stays on.
Keyboard
- Click the widget once so it has focus, then: Space replay the progression.
- 1–8 place the numeral in that position of the grid (the small grey digit on each button is its key).
- Backspace undo the last placement, Delete clear all slots.
- Enter submit — or, once a round is marked, move on to the next round.
- N new round, T tonic reference, W play-along walk-through, R reveal.
- ← / → nudge the volume — but never while a slider has focus, where the arrows belong to the slider.
Tips
Listen to the bass line first. The lowest note is always the chord root, so if you can sing the bass against the tonic you have already named the progression: down a step then up a fourth is vi–IV, a rise of a fourth is I–IV or V–I.
Next, judge bright or dark on each chord: major or minor. In a major key only ii iii vi are minor, so one dark chord in a four-chord pop loop is almost always vi. Start with three chords and the pop pool only; add jazz and minor once you are hitting eight rounds in ten.
The idea behind this virtual instrument is to train your ear to hear chord progressions not by their absolute pitch but by there function. Each round presents you with a sequence played in a randomly chosen key, which you then has to work out the harmonic role of each chord in relation to the tonic. You can use the widget on a touch screen or with a mouse. Alternatively, you can use a computer keyboard if you want something faster.
The aim is that you will develop an internal map of how chords relates to one another across various styles of music. Press the Play progression button to listen to the next round. First you will hear the tonic reference chord that acts as a tonal anchor, followed by the progression. Clicking on the button (or pressing the spacebar) replay the sequence as many times as you like.
How to Use the Chord Trainer
If you get lost at any point the Tonic reference button isolates the home chord so that you can easily re-set your ear. As you listen to following harmonies, keep the root note of this chord in mind, because all other notes are defined by how they sound compared to it. Each chord in the progression has an empty slot in the answer area. To fill one, tap on the corresponding Roman numeral in the grid above. The numerals use different cases. Upper-case means major triads. Lower-case means minor. A degree symbol means diminished.
Once you’ve made a mistake, you can clear any filled slot by tapping it again, or press Undo to delete most recent one. Pressing Clear deletes all entries at once, allowing you to begin anew without altering the underlying progression. Once you’ve entered all the chords click on Submit. Your answers will be color coded with checks for green chords and x’s for red chords. Any wrong ones will have the correct numeral displayed below them.
If you’re stumped you can click the Reveal button which instantly displays the correct progression but this also deducts an attempt from your score. Once marked, the play-along button will activate. This allows you to walk through each progression chord by chord. The correct numeral will highlight as the sound plays, so you can link visual label to the sound you hear.
In the settings panel, you can set the difficulty to suit your existing ability. This includes the length of Progression (3/4 or 4 chords). It also includes As written (for longer versions such as Blues progressions and Pachelbel canon). You can set Chord speed (Slow, Med, Fast) and the type of chords included in the Difficulty pool (Common pop progressions, Jazz ii-V-I patterns and/or Minor keys). At least one pool should be switched on at any time.
Once you’ve got the widget in focus, practice becomes fluid and quicker thanks to keyboard shortcuts. To add corresponding Roman numeral in the grid straight to your answer slot, press the relevant number key between 1 and 8. Delete will clear all of the slots, while backspace undoes your previous action. If you’re on a round that’s already ticked, you can hit enter to go to the next round or submit an answer.
For other options, hit R to show the answer, T to bring up the tonic reference, W to start the play-along walk-through, or N for a new round. The master volume can be altered with arrow keys rather than dragging it around too.
It’s also useful to keep track so you can see where you’re making progress, and where you might need a little more practice. In the stats section, you’ll find your score to see where you left off. You can also see your current and best streaks, along with the percentage of chords you’ve accuratly identified. Next, the breakdown list shows your accuracy for each progression… It will tell you how well you know each specific chord progression you’ve come across. So it shows you where you’re comfortable harmonically and where you need some extra time. Set yourself up to focus on the ones you aren’t as good at with length or pool setting.
If you’re not sure where to begin, listening out for the bass line can be a useful tactic; after all it’s typically the lowest note so it will give you the clue that is most likely the chord root. You’ll also want to figure if the chord is ‘dark’ or ‘bright’, which points towards its major/minor quality. Minor chords only exist on the ii, iii and vi in major keys. To gain confidence work through some of the more popular three-chord progressions and then try the pool of common chords used in pop. As your ear gets better, try including minor and jazz keys.
There’s also a fullscreen option for distraction-free practice, and the widget automatically toggles to dark mode based off your surroundings. For those who might need a reminder on how it works, there’s a handy help panel which includes a quick reference guide for keyboard controls along with Roman numeral notation. If you’d like to reset everything and go back to square one (or perhaps start a new streak), there’s also a reset option that will wipe out all of the settings and scores.
Replay through it as many times as you need to feel comfortable with how the harmonic movement works, and take your time on each round. Early on, there’s no need for accuracy, as you’re simply developing an ear that can hear the music functionally rather then by exact note or pitch. The submit and play-along features gives instant feedback so that you link symbol to sound to theory in real-time and really speed up your learning. Start building your intuitive sense of harmony now. Press play.