What does "coverage" mean?

Coverage is the number of your selected notes that also appear in the key's seven-note major scale, divided by the total notes in that scale. A 100% match means every note you selected fits perfectly in that key.

Why are multiple keys shown?

Most melodies use fewer than seven notes, so several keys can share those notes. The tool ranks all candidates so you can use musical context — like the final chord — to pick the best fit.

What is the relative minor?

Every major key shares its seven notes with one natural minor key that starts a minor third (three semitones) lower. For example, C major and A minor use the same notes. Both are listed for each result.

Should I include sharps and flats?

The 12 buttons represent pitch classes (C, C#/Db, D … B). Select whichever notes you hear, using enharmonic equivalents freely — C# and Db are the same button.

What if no key scores 100%?

You may have selected notes outside the key (chromatic passing tones, borrowed chords) or the song uses a mode or scale other than major. Try removing one note at a time to see which omission raises the top score.

Song Key Detector Helper

Name: Song Key Detector Helper
Availability: InStock
Author: Nham Vu

Select the notes you hear in a song and the tool ranks all major keys and their relative minors by how many of those notes they contain.

Select Notes You Hear

Click to toggle. Select every pitch class present in the song.

Key Candidates (select notes above)

Select at least one note to see key matches.

Major Key Reference (notes in each key)

Key	Notes

Summary

Select the notes you hear in a song and the tool ranks all major keys and their relative minors by how many of those notes they contain.

How it works

Click the note buttons to select every pitch class you can hear or identify in the song.
The tool compares your selection against all 12 major key signatures.
Each key is scored by how many of its seven notes match your selected notes.
Results are ranked from highest to lowest coverage, with the top match highlighted.
The relative minor (same key signature, starts a minor third lower) is shown alongside each major candidate.
Deselect notes or click Reset to start over with a different set.

Use cases

Identify the key of a song by ear before writing chord charts.
Narrow down key candidates when transcribing a melody.
Teach students how note sets map to key signatures.
Cross-reference with a capo or transposer to find guitar-friendly keys.
Confirm a suspected key by checking whether all chord tones belong to it.
Quickly explore which keys share a given set of notes for modulation ideas.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu