The Locrian mode, explained: sound, notes, and how to use it

The Locrian mode is the one every list of modes saves for last, usually with a warning attached. A mode is a scale you get by taking the seven notes of a major scale and starting on a different one of them: the notes stay the same, but starting from a new spot changes how the scale sounds, and with seven notes to start from you get seven modes, each with its own character. If you want the bigger picture of how scales and keys shape a song's mood first, our guide to how each musical key feels is a good companion read, and if you have already met the Dorian, Phrygian, Lydian, Mixolydian, and Aeolian modes, Locrian is the seventh and strangest of the set. Built on the seventh degree of the major scale, it is the only mode whose home chord is a diminished triad, which makes it dark, unstable, and famously hard to write a whole song in. You can find it on a piano by playing the white keys from B to B, that is B, C, D, E, F, G, A, and that is B Locrian. This guide walks through what modes are, how to build Locrian in any key, why it sounds so restless, the chords it produces, and how to write and hear it for yourself in Flat.

What are the modes?

A mode is a scale you get by taking the notes of a parent scale and treating a different note as home. Start the C major scale on C and you get the familiar major sound, known as Ionian. Keep the same seven notes but treat B as home instead, and the arrangement of whole steps and half steps shifts, so the scale takes on a different character even though not a single note has changed. That shift is what a mode is.

The major scale is where all seven modes come from. Play a C major scale, which has no sharps or flats, then play those same seven notes again but start and finish one note higher each time. Every one of those seven scales is a mode, and each has its own name, its own pattern of steps, and its own mood:

Mode	Starts on (in C major)	Notes	Feel
Ionian	C (1st)	C D E F G A B	Bright and settled, this is the major scale
Dorian	D (2nd)	D E F G A B C	Minor, but warm and hopeful
Phrygian	E (3rd)	E F G A B C D	Minor and dark, with a Spanish tinge
Lydian	F (4th)	F G A B C D E	Major, but bright and dreamy, floating
Mixolydian	G (5th)	G A B C D E F	Major, but bluesy and relaxed
Aeolian	A (6th)	A B C D E F G	Minor, this is the natural minor scale
Locrian	B (7th)	B C D E F G A	Unstable and tense, rarely used on its own

You already know two of these without thinking of them as modes. Ionian is simply the major scale, and Aeolian is the natural minor scale, the two sounds most music leans on. The other five sit in between and give you moods that plain major and minor cannot reach on their own, which is exactly why composers, film scorers, and songwriters keep them in their back pocket.

What decides whether a mode sounds major or minor is its third note, counting up from home. When that third is a major third above the starting note, the mode leans bright and major: that is the case for Ionian, Lydian, and Mixolydian. When the third is a minor third, the mode leans darker and minor: Dorian, Phrygian, Aeolian, and Locrian. Locrian is the seventh mode, built on the seventh degree of the major scale, and it sits at the far dark end of that minor group, set apart by one extra alteration that none of the others share.

What is the Locrian mode?

The Locrian mode is the seventh mode of the major scale, and there are two reliable ways to build it depending on how you think.

The first is the relative, or derivative, method: take any major scale and start on its seventh note. B Locrian comes from C major, so you play the notes of C major from B up to B and land on B, C, D, E, F, G, A. By the same logic, F♯ Locrian comes from G major and E Locrian comes from F major. It is the same handful of notes, simply centred on a new home.

The second is the parallel method, which starts from the major scale on your target note. B major is B, C♯, D♯, E, F♯, G♯, A♯; to get B Locrian you lower the second, third, fifth, sixth, and seventh degrees by a half step, leaving B, C, D, E, F, G, A. That is five lowered notes, more than any other mode changes, and the first sign of how far Locrian sits from a bright major scale. In scale-degree terms, Locrian is 1, ♭2, ♭3, 4, ♭5, ♭6, ♭7, and its step pattern is half, whole, whole, half, whole, whole, whole.

Here is the detail that defines the whole mode. Every other mode has a perfect fifth above its tonic, a stable interval that gives the ear a solid home. Locrian does not: its fifth is lowered to a diminished fifth, the tritone. Line it up against the major scale on the same note and five notes move, but that lowered fifth is the one that matters most.

Degree	B major (Ionian)	B Locrian
1	B	B
2	C♯	C (lowered)
3	D♯	D (lowered)
4	E	E
5	F♯	F (lowered)
6	G♯	G (lowered)
7	A♯	A (lowered)

That lowered fifth is why Locrian behaves unlike any other mode. Build a triad on the tonic, stacking B, D, and F, and you get a diminished chord instead of the major or minor chord every other mode gives you. A diminished tonic has no stable ground to rest on, so the scale never really settles, which is exactly why Locrian is treated as the odd one out. If theory videos help it click, this walkthrough builds the mode step by step:

What the Locrian mode sounds like

Locrian is a minor mode, since its third is lowered, but the diminished fifth takes it somewhere the other minor modes never go: it sounds tense, dark, and unresolved, like music that is holding its breath. That instability is the whole point, and it is also why you almost never hear a full song written in Locrian the way you would in Aeolian or Dorian. It is the only modern diatonic mode whose tonic triad is a diminished chord, and that dissonant tonic is what keeps it from feeling like a comfortable home key.

Instead of anchoring a whole piece, Locrian tends to show up as color. You will hear it in metal and other heavy styles, where the tension is the appeal, and jazz players reach for it as the scale that fits a half-diminished chord, the m7♭5 that opens a minor two-five-one. The quickest way to feel what makes it modal is to play the scale and try to end on B: the ear keeps wanting to slip somewhere more stable, because there is no strong fifth pulling home. This breakdown of the mode in real music is a good ear-opener:

Locrian chords and progressions

Harmonize the B Locrian scale in thirds and you get these diatonic triads:

Scale degree	Chord	Notes
i°	B diminished	B, D, F
♭II	C major	C, E, G
♭iii	D minor	D, F, A
iv	E minor	E, G, B
♭V	F major	F, A, C
♭VI	G major	G, B, D
♭vii	A minor	A, C, E

The most recognizable Locrian move is the diminished tonic leaning into the bright major chord a half step above it: B diminished to C major, the i°–♭II pairing that captures the mode's uneasy character in two chords. That C major sitting right against the tonic is the harmonic version of the lowered second, and the clash between the two is unmistakably Locrian. Because the tonic chord is diminished, it never provides the resolution a major or minor key would, so progressions in Locrian tend to circle rather than land.

This is why Locrian is used differently from the other modes. Rather than building a whole key around it, most writers use it in two ways: as a source of dark, tense color in a passage that resolves elsewhere, or as the exact scale to play over a single B half-diminished chord (Bm7♭5), which is where it earns its keep in jazz. Keep the diminished tonic in view, lean on the ♭II for that half-step brightness, and treat the mode as a splash of tension rather than a place to settle. For more on how chord choices carry feeling, see our guide to chord progressions and the emotions they create, and to pick a comfortable starting key, read our overview of how to choose the right key.

How to write in the Locrian mode in Flat

You do not need a special mode button to write in Locrian. The trick is to choose the right key signature and anchor your music on the right tonic, keeping in mind that Locrian works best in short doses. There are two reliable ways to set it up.

The first is to borrow the parent major key signature. For B Locrian, set the key signature to C major, with no sharps or flats, using Flat's key signature tool, then centre your phrases on B so the ear hears B as the reference point. The second is to write your idea once and move it: compose in B Locrian, then use Flat's transpose tool to shift the whole passage to E Locrian, F♯ Locrian, or whatever key suits your instrument. Either way, press play as you go, because Flat's audio playback lets you hear the tension straight away, even for instruments you do not play yourself.

Try this in Flat, in about two minutes:

1. Open a new score and set the key signature to C major, the one with no sharps or flats.
2. On the staff, click in these notes one after another: B, C, D, E, F, G, A, then B again. That line of notes is the B Locrian scale.
3. Add a piano part underneath and give it two chords: B diminished (B, D, and F) for two bars, then C major (C, E, and G) for two bars.
4. Press play. That i°–♭II move, B diminished to C major, is the sound of Locrian in miniature: an unstable, dissonant home leaning into the bright chord a half step above, and never quite resolving.

Ready to hear the Locrian mode in your own music? Try Flat for free and write your first modal idea in minutes.