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B Diminished Major 7th

Diminished Major 7th · B – D – F – A♯

The B Diminished Major 7th chord (Bdim(maj7)) contains the notes B, D, F, and A♯. Its interval formula is 1 ♭3 ♭5 7. A diminished triad with a major 7th — rare and unstable, used for chromatic color in jazz.

At the keyboard

B · D · F · A#
Maintained by Justin Evans, a pianist of 25 years
Maintained for accuracy · Last updated July 2026 · How we review
Flashcards · Chord
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B

The B Diminished Major 7th chord is a four-note chord made up of B, D, F, and A♯.

Construction

B Diminished Major 7th = Root + Minor 3rd + Diminished 5th + Major 7th = B · D · F · A♯
NoteIntervalDegree
BRoot1
DMinor 3rd♭3
FDiminished 5th♭5
A♯Major 7th7

Key Signature

A Diminished Major 7th chord is built from symmetrical or ambiguous intervals, so it doesn’t belong to a single key and has no key signature of its own.

B Diminished Major 7th — Frequently Asked Questions

What is the B Diminished Major 7th chord on piano?
The B Diminished Major 7th chord contains the notes B – D – F – A♯. On piano, play these notes together to sound the chord.

Related Tools

Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.

References & Further Reading

The note names, intervals, fingering, and harmony on this chord page are grounded in the following sources. Public domain treatises and scores are linked to their full text; primary data is piano.org's own interval-derived reference dataset — continuously maintained and human-verified, with no fixed publication date.

  1. 1

    Goetschius, Percy(1889)

    The Material Used in Musical Composition

    Public domain treatise
  2. 2

    Riemann, Hugo(1896)

    Harmony Simplified (English translation)

    Public domain treatise
  3. 3

    George Grove (ed.)(1900)

    A Dictionary of Music and Musicians

    Public domain treatise
  4. 4

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