How to Find the Key of a Song by Ear (Step by Step)

Here is how to find the key of a song: collect the notes you hear in the melody, bass and chords, compare them with the major and minor scales that contain them, and then decide which note feels like home. The free key and scale finder does the comparison for you: tap the notes you hear and it ranks the most likely keys, shows the full scale and lists any notes that fall outside it.

What “key” actually means

A key is a set of seven notes (a scale) plus a home note, called the tonic, that the music keeps resolving to. C major uses C, D, E, F, G, A and B, with C as home. A minor uses exactly the same seven notes, but A feels like home. That is why finding a key always has two parts: which notes and which note is home.

Knowing the key lets you write parts that fit, choose samples that will not clash, tune vocals to the right scale, and talk to other musicians quickly.

Step 1: Find the home note

Play the song and hum one note that feels like it could end the song. This is usually:

• the last note of the melody, or the last bass note;
• the root of the first or last chord;
• the note the chorus keeps landing on.

Find that note on a keyboard, a guitar or an online piano by matching it until the two sound the same. This is your best guess for the tonic. Keep it in mind, but do not lock it in yet.

Step 2: Collect the notes you hear

Next, work out the other notes in the song. The bass line is a good place to start because it is usually simple and clear. Then add notes from the main melody and the chords.

Open the key and scale finder and tap each note as you find it. You do not need to enter them in order, and repeating a note does not count twice. After three notes the tool starts suggesting keys; five to seven distinct notes give a much more reliable answer.

Step 3: Read the ranked keys

The finder compares your notes with all 36 major, natural minor and harmonic minor scales. Keys that contain the most of your notes rank highest, with a bonus when the tonic chord and your chosen home note are in the set. For each suggestion you see the full scale and the notes you entered that sit outside it.

If the top result contains every note you entered, you are almost certainly in that key or its relative major or minor.

Step 4: Choose between major and its relative minor

Every major key shares its notes with one minor key. The finder will often show both near the top, because the notes alone cannot separate them. Use your ears and the home note:

Relative pair	Shared notes	Major if home is…	Minor if home is…
C major / A minor	C D E F G A B	C	A
G major / E minor	G A B C D E F#	G	E
F major / D minor	F G A Bb C D E	F	D
D major / B minor	D E F# G A B C#	D	B

Set the home note in the finder and it will favour the matching key. A song that sounds bright and settled on the home chord is usually major; a darker, heavier resolution usually points to minor.

Step 5: Handle notes that do not fit

Real songs borrow notes from outside their key all the time. The finder still shows the closest match and lists the outside notes, so you can judge whether they are passing colour or a sign that you have the wrong key.

• A raised seventh in a minor key, such as G# in A minor, usually points to harmonic minor. The finder includes harmonic minor scales for this reason.
• One odd note in a single chord is often a borrowed chord and does not change the key.
• Several outside notes in one section may mean the song modulates. Find the key of each section separately.

Worked example

Say the bass line uses A, C, D and E, the melody adds G and B, and the song keeps resolving to A. Entering A, B, C, D, E and G gives C major and A minor as the top matches, because both contain all six notes. Setting the home note to A puts A minor first. If a chorus chord adds G#, the finder lists G# as an outside note for A natural minor and ranks A harmonic minor highly, which tells you the song uses the raised seventh on that chord.

When you have a recording instead

Working by ear trains your hearing and works on any song, but if you have the audio file, our BPM and key finder analyses the file in your browser and estimates both the tempo and the key. Use it as a starting point and confirm the result by ear, especially on songs with heavy distortion, lots of drums or key changes.

What to do once you know the key

• Set the scale in your vocal tuner or MIDI scale tool so new parts stay in key. Our vocal tuner helps you check sung pitch.
• Build a progression from the scale’s chords with the chord progression generator.
• Use the circle of fifths to find closely related keys for a bridge or a modulation; our guide on how the circle of fifths is used explains how.

Common mistakes

• Guessing from the first chord only. Many songs start away from home. Check where the song resolves.
• Ignoring the relative minor. C major and A minor share notes; the home note decides between them.
• Entering too few notes. Three notes fit many keys. Aim for five to seven.
• Treating every outside note as a key change. Borrowed notes are common; look for a pattern before deciding the key has changed.
• Trusting audio detection blindly. Automatic detection can confuse relative keys. Always check with your ears.

FAQ

For the theory behind scales and keys, browse our music theory guide or the overview of musical keys on Wikipedia. Have a melody stuck in your head? Tap its notes into the free key and scale finder and get the key in seconds.