Chord Finder

Chord finder: choose the written root before the sound

A chord finder builds a named chord from its root, quality, and optional chord inversion. It answers questions such as “Which notes spell F-sharp minor?” It does not listen to a recording or identify an unknown harmony from audio.

The quickest dependable lookup

1. Choose the root exactly as it appears in the score or chord symbol.
2. Select the quality: major, minor, diminished, augmented, suspended, or a supported seventh chord.
3. Begin in Root position and read the note names and formula.
4. Use the keyboard map to see pitch classes, then play the chord quietly.
5. Choose an inversion only after the root-position spelling is clear.

The interface supports major, minor, diminished, augmented, sus2, sus4, dominant 7, major 7, minor 7, half-diminished 7, and diminished 7. Third inversion is available only for four-note chords, because a triad has no fourth chord tone to place in the bass.

Worked examples: F-sharp minor and B-flat dominant seventh

Choose F# and Minor. The formula is 1, flat 3, 5, and the notes are F-sharp, A, C-sharp. The letter sequence matters: a triad uses alternating letter names, so the fifth is written C-sharp rather than D-flat even though those keys sound alike in equal temperament.

Choose B-flat and Dominant 7. The formula is 1, 3, 5, flat 7, producing B-flat, D, F, A-flat. In first inversion, D moves to the bass; in second inversion, F is lowest; in third inversion, A-flat is lowest. The chord identity remains B-flat dominant seventh because inversion changes order, not membership.

Why spelling matters

C-sharp and D-flat can share a key on an equal-tempered keyboard while doing different harmonic jobs. A chord rooted on C-sharp should normally preserve the appropriate sequence of letter names. Correct spelling reveals scale degree, voice leading, and the interval structure that a list of keyboard buttons can hide.

The displayed semitone formula is useful for checking sound, but semitones alone do not determine the written result. Major and diminished structures require specific thirds and fifths. Read the spelled notes before using playback as confirmation.

Inversions and practical voicing

An inversion names which chord member is in the bass. It does not prescribe the exact octave, doubling, spacing, or instrumental voicing. A pianist may spread a chord across both hands; a guitarist may omit or double a tone; an arranger may distribute notes through an ensemble while preserving the same bass member.

Use the result as a harmonic reference, then adapt it to range and style. If a playback sounds muddy, move notes into a practical register rather than changing the chord label. The tool’s one-octave keyboard is a pitch-class map, not a complete orchestration.

Read formulas as interval recipes

A major triad uses root, major third, and perfect fifth: semitone offsets 0, 4, 7. Minor changes the third to 0, 3, 7. Diminished lowers both third and fifth to 0, 3, 6, while augmented raises the fifth to 0, 4, 8. Suspended chords replace the third with degree 2 or 4, which is why they do not sound simply major or minor.

Seventh chords add one more member. Major 7 uses 0, 4, 7, 11; dominant 7 lowers that last interval to 10; minor 7 combines a minor triad with the ten-semitone seventh. Half-diminished 7 uses 0, 3, 6, 10, while diminished 7 contracts the final interval to 9. The displayed scale-degree formula keeps those differences visible.

Use inversion to follow bass motion. A progression may keep common upper tones while the bass moves through first or second inversion, creating smoother voice leading than a sequence of root-position blocks. The finder shows which chord member is lowest; it does not choose the best doubling. Play the result, then arrange its notes within the range and texture of the actual instrument or ensemble.

On a keyboard, play the displayed tones in close position, then move the upper notes by octaves while keeping the named bass member. On guitar, one or more tones may be doubled or omitted because of fingering and string range. Compare the sounding pitch classes with the finder, but judge the voicing on the instrument. A playable shape can represent the correct chord without reproducing the compact keyboard layout.

Errors the tool can and cannot solve

• A wrong root or quality produces a correct answer to the wrong symbol.
• Enharmonic root choices change spelling even when playback can sound identical.
• Third inversion does not apply to a three-note chord.
• Playback confirms pitch content but not voicing quality on a real instrument.
• Audio chord recognition requires another tool and remains sensitive to tuning, timbre, and missing tones.

Read Open Music Theory on triads or the general chord overview for notation context. Use the interval trainer to hear the component distances, or return to all Sound Lab tools.