How are chords built?

Chords are built by stacking intervals on top of a root note. A major chord uses the root, major third (4 semitones) and perfect fifth (7 semitones). A minor chord uses root, minor third (3 semitones) and perfect fifth (7 semitones).

What is a seventh chord?

A seventh chord adds a fourth note — the seventh interval — on top of a triad. Major 7th adds the note 11 semitones above the root, dominant 7th adds 10 semitones, and minor 7th adds 10 semitones on top of a minor triad.

Suspended chords replace the third with either the second (sus2) or fourth (sus4) scale degree. They sound neither major nor minor and create tension that typically resolves to a major or minor chord.

AudioCalcs

Chord Calculator — Build Chords from Root Note

Build chords from any root note. See the notes, intervals and chord-tone frequencies.

Root NoteThe root note the chord is built from (C to B). All tones are shown with sharp spelling.

Chord TypeChord quality — triads (major, minor, dim, aug, sus2/sus4) or seventh chords (maj7, min7, dom7, dim7).

How We Calculate This

Each chord type is defined by a set of intervals (in semitones) from the root note. The calculator adds these intervals to the root note index and wraps around using modulo 12 arithmetic to name each tone.

Each tone's pitch is then found with the 12-tone equal-temperament formula f = ref × 2^((MIDI − 69)/12), where the reference is A4 (MIDI 69, 440 Hz by default) and the MIDI number is 12 × (octave + 1) + the tone's position above C. For example, a C major triad at octave 4 gives C4 = 261.63 Hz, E4 = 329.63 Hz and G4 = 392.00 Hz.

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Last updated: February 2026

All calculations are estimates based on standard formulas. Always verify results for critical applications.