To play Bdim on the ukulele, you need the notes B, D, F. Its first ukulele voicing is the open position: G string at fret 4 (little finger); C string at fret 2 (middle finger); E string at fret 1 (index finger); A string at fret 2 (ring finger). This guide covers the diminished chord in full: what is in it, how to play it cleanly on the ukulele, where it fits musically and how to practise it.
What notes are in the Bdim chord?
The Bdim chord is a diminished chord, and its notes are fixed: B, D, F. Every voicing on every instrument uses these same notes, in some order and in some octave — change one of them and you are playing a different chord. The table below lists each note with its interval from the root B, so you can see the structure of Bdim at a glance. On the ukulele, the open position of Bdim puts those notes under your fingers in the order the fingering lists them.
| Note | Interval |
|---|---|
| B | Root |
| D | b3 |
| F | b5 |
The root is B, the note the chord is named after and the note your ear hears as home. Above it, the intervals in Bdim are b3, b5. That combination is what makes Bdim sound the way it does: the intervals decide the colour, and the root decides the pitch. On the ukulele, the notes appear in the order the fingering dictates, but the set of notes never changes.
Bdim sounds tense, dark and unstable — the flattened 5th ({flat5}) makes the chord want to move somewhere, anywhere. The colour is strongest when all the notes ring clearly. A muted chord tone, especially the 3rd or the 7th where the chord has one, flattens the character of Bdim noticeably. On the ukulele, the open position voicing is the place to hear it in Bdim.
Comparing Bdim with its closest relatives helps to fix it in your ear. In short, diminished against minor: both have the minor 3rd D, but Bdim flattens the 5th to F where the minor chord keeps the perfect 5th F#. Practise the two chords back to back and listen to the one note that changes — that single note is the difference between the two chords. On the ukulele, start with the first voicing above and listen for the notes B, D, F in Bdim.
How to play Bdim on ukulele
On the ukulele, Bdim has 3 voicings in the data below, and each one uses the same notes — B, D, F — in a different place on the neck. Start with the first voicing and get it clean before you try the movable shapes further up the neck. Finger numbers below use 1 for the index finger, 2 for the middle finger, 3 for the ring finger and 4 for the little finger, and x means the string is not played.
Another way to play Bdim is the open position, in open position: G string at fret 4 (little finger); C string at fret 2 (middle finger); E string at fret 1 (index finger); A string at fret 2 (ring finger). The stretch is the challenge: the fretted notes span from fret 1 to fret 4, so keep your thumb low behind the neck and let your fingers reach rather than squeezing the neck. Strum or pluck it slowly first and check that every note in Bdim — B, D, F — sounds, with no buzz and no accidental open string.
Another way to play Bdim is the barre chord, in around fret 5: G string muted; C string at fret 5 (index finger); E string at fret 7 (middle finger); A string at fret 5 (index finger). It barres across strings 2 to 4 at fret 5 with the index finger. The barre is the hard part: the index finger must press every string from 2 to 4 evenly at fret 5, so roll it slightly onto its bony side and keep it close to the fret wire. If the barre buzzes, move it a fraction closer to the fret and press from the arm, not the thumb alone. Strum or pluck it slowly first and check that every note in Bdim — B, D, F — sounds, with no buzz and no accidental open string.
The movable voicing puts Bdim in around fret 4: G string at fret 4 (index finger); C string at fret 5 (middle finger); E string at fret 7 (little finger); A string at fret 5 (ring finger). The stretch is the challenge: the fretted notes span from fret 4 to fret 7, so keep your thumb low behind the neck and let your fingers reach rather than squeezing the neck. Strum or pluck it slowly first and check that every note in Bdim — B, D, F — sounds, with no buzz and no accidental open string.
Choosing between the voicings of Bdim is a musical decision, not a right-or-wrong one. The open or low-position voicing rings the most and suits strumming, while a barre or movable voicing lets you slide Bdim up the neck to any key without changing the shape. When you change chords, pick the voicing of Bdim that sits closest to the chord before it — shorter moves between shapes mean faster, cleaner changes. Practise the change into Bdim from the chord that comes before it in your song, not the chord on its own, because the move is the skill. On the ukulele, start with the first voicing above and listen for the notes B, D, F in Bdim.
A short practice routine for Bdim on the ukulele: play the first voicing four times slowly, checking each note, then change to it from the chord a fourth above B and back, four times, at a slow tempo. Then play the second voicing the same way. If a note buzzes, stop and fix the finger placement rather than playing through the buzz — clean notes at a slow tempo become clean notes at full tempo, while buzzes practised fast become habits. Use the Ukulele Chord Finder to see the diagram for Bdim while you practise, and the Chord Finder to compare it with the same chord on other instruments.
Common mistakes
These are the mistakes that most often make Bdim sound wrong on the ukulele, and each one has a concrete fix. Work through them one at a time rather than trying to fix everything at once.
Voicing it too low. A diminished triad low down sounds muddy because its notes are close together. Use a higher voicing or spread the notes across octaves. On the ukulele, start with the first voicing above and listen for the notes B, D, F in Bdim.
Confusing it with the half-diminished 7th. The half-diminished chord adds a flattened 7th to this triad. Bdim on its own has only three notes: B, D, F. On the ukulele, the open position voicing is the place to hear it in Bdim.
Pressing too hard on the nylon strings. Ukulele strings need far less pressure than guitar strings, and pressing hard on Bdim pulls the notes sharp and tires the hand. Use the lightest touch that gives a clean note, and keep your fingers close to the frets. On the ukulele, the open position of Bdim puts those notes under your fingers in the order the fingering lists them.
Playing a perfect 5th. If the 5th is F# instead of F, the chord is minor, not diminished. The flattened 5th is the note that defines this chord. On the ukulele, start with the first voicing above and listen for the notes B, D, F in Bdim.
Where Bdim is used
As a diatonic chord, Bdim belongs to the key of C major, the key of A minor. In those keys it is one of the seven chords built from the key's own notes, so it fits without any chromatic notes. the vii° chord in major keys, leading straight to the tonic. That is the practical meaning of belonging to a key: the chord sounds settled there, and the other chords of the key lead to it and away from it naturally. On the ukulele, the open position voicing is the place to hear it in Bdim.
Because Bdim is an extended or altered chord, it appears in progressions as a colour or a dominant rather than as a diatonic staple. Try it in place of the plain B triad in a progression you already know, and listen to how the extra notes change the feel — that substitution is the usual way extended chords enter real music. The Chord Progression Builder lets you try Bdim in a progression in any key and hear how it connects to the chords around it. On the ukulele, the open position voicing is the place to hear it in Bdim.
The same chord on other instruments is covered in Bdim on guitar, Bdim on piano, Bdim on bass, and the scales that fit over it are the B major scale and the B minor pentatonic scale. Learning Bdim on the ukulele and then checking it on another instrument is one of the best ways to fix the notes — B, D, F — in your memory, because the notes stay the same while everything else changes.
Practising Bdim
A short worked example makes Bdim concrete. Play the four-chord progression C – G – Am – F in C major, where Bdim is diatonic: C – G – Am – F. Play each chord for one bar at a slow tempo, and listen to how Bdim sounds in that sequence — whether it feels like home, like a lift, or like a chord on its way somewhere else. Then play the same four chords in a different order, starting on Bdim itself, and notice how its character changes when it opens the progression instead of sitting inside it. On the ukulele, the open position voicing is the place to hear it in Bdim.
For a second exercise, play Bdim and then the chord a fourth above B, back and forth, four times each. That move — a chord and the chord a fourth above it — is the most common resolution in Western music, and it is the move Bdim is built for when it acts as a dominant. Finish by playing Bdim on its own, slowly, and naming each note out loud as you play it: B, D, F. Naming the notes while you play them is what turns a shape into knowledge you can use in any key. Test yourself with the Practice Chord Quiz and keep time with the Metronome as the tempo rises. On the ukulele, start with the first voicing above and listen for the notes B, D, F in Bdim.
Frequently asked questions
What is the easiest voicing of Bdim on the ukulele?
The open position is the easiest voicing listed for Bdim on the ukulele: frets 4–2–1–2, fingers 4–2–1–3. Learn that shape first, get every note ringing cleanly, and only then move on to the alternative voicings further up the neck.
Why does Bdim sound tense?
Its 5th is flattened to F, a tritone above the root B. The tritone is the most unstable interval in Western music, and it makes the chord want to resolve. On the ukulele, check the first voicing above for that note.
What notes are in Bdim?
Bdim contains B, D, F: the root B, the minor 3rd D and the diminished 5th F. It is two minor 3rds stacked — B to D, then D to F. On the ukulele, check the first voicing above for that note.
Where is Bdim used?
Most often as the vii° chord in a major key, leading to the tonic, and as a passing chord between two chords a whole step apart. It also substitutes for a dominant 7th chord. On the ukulele, check the first voicing above for that note.
How do you play Bdim on the ukulele?
The first voicing is the open position: frets 4–2–1–2, fingers 4–2–1–3, on the ukulele. That voicing uses the notes B, D, F, and it is the one to learn first. The page above lists more voicings for Bdim, so you can choose the shape nearest the chords around it.