Reference · Finding the key of a record

How to find the key of a song

The key is the note a song keeps coming home to, named on an instrument, plus whichever third agrees with it: a major third means a major key, a minor third means a minor key. That takes a minute or two by ear on anything with pitched content. A part with no pitched content has no key to find, so a drum loop returns nothing, by ear or by software.

Session™ Key, described further down this page, is published by Capiscana, Inc., which operates this site. Facts about it are dated to the day the source was read.

The ear method, step by step

This is the method that works without any software, and it is the one worth learning first, because it is the only one that also tells the ear what it is listening for.

1. Find the note of restPlay the song and hum along until the voice settles on the note where the music sounds finished. Verses and choruses keep returning to it. That note is the tonic.
2. Name it on an instrumentHunt the hummed note down on a piano, a keyboard or a guitar until the two pitches match. The tonic now has a name, and that name is the first half of the key.
3. Play both thirds over itHold the tonic and play the note four semitones above it, then the note three semitones above it. One of the two belongs to the record. Four semitones is a major key, three is a minor key.
4. Check it against the bassListen to the bass note under the final chord of the chorus and compare it to the hummed note. When they disagree, the hum landed on the fifth or the third rather than the tonic, which is the single most common way this method goes wrong.

The two places it goes wrong

Humming the fifth. The fifth is the second most stable note in a key and a voice settles on it readily, which puts the answer a perfect fifth away from the truth: hearing G in a song in C major. Step four above catches it, because the bass under a final chord lands on the tonic rather than the fifth.

Confusing the relative minor. C major and A minor contain the same seven notes, so a chord progression alone does not separate them. What separates them is which note the music treats as home.

Two further cases have no single right answer. A record that modulates has one key before the change and another after. A record built on a mode sits between the major and minor labels, and naming it either way loses something.

Reading the key from a Mac's audio output

Session™ Key is a macOS menu bar app that reads the key and the BPM of whatever is playing through the Mac's audio output and shows both in the menu bar. The source is the machine's own output, so a streaming reference, a browser tab, a voice memo and a bounce in a DAW are all read the same way. Detection runs on the device and no audio is uploaded, recorded or stored.

Every read carries a confidence mark, and when two keys are equally defensible the app names both rather than picking one silently. One keystroke then writes the key and the tempo into Pro Tools, Logic Pro, Ableton Live or Studio One. FL Studio has no project key field, so only the tempo is written there.

What it costs and what it runs on

Common questions

How do you find the key of a song by ear?

Hum along until the voice settles on the note where the song sounds finished, match that note on a keyboard, then play a major third and a minor third over it. Whichever third agrees with the record names major or minor, and with the tonic that is the key.

What if the hummed note sounds wrong against the record?

Compare it to the bass note under the final chord of the chorus. A voice settles on the fifth almost as readily as on the tonic, and that puts the answer a perfect fifth away from the truth.

How is a major key told apart from its relative minor?

By which note the music treats as home, not by the notes. C major and A minor contain the same seven notes, so the scale cannot separate them and only the point of rest can.

Can the key of a drum loop be found?

No. Unpitched material has no tonal center, so there is no key to find, by ear or in software. A tool that returns a key for a bare drum loop is reporting resonance rather than a key.

Is there a way to find the key on a Mac without uploading the file?

Yes. Session™ Key reads the key from the Mac's own audio output while the track plays. Detection runs on the device, so nothing is uploaded, recorded or stored.