Chord Finder

Pick a root note and chord type to see the notes, interval formula, and reference pitch, calculated with standard 12-tone equal-temperament chord theory.

Quick Facts

Method
12-tone equal-temperament chord construction
Chords stack fixed semitone intervals above a root note within the 12-note chromatic scale (major triad = root, +4, +7 semitones).
Tuning reference
A4 = 440 Hz
Frequencies use f = 440 x 2^((n-69)/12), where n is the MIDI note number.

Your Results

Calculated
Chord
-
Root + quality + symbol
Notes in chord
-
Sharp spelling, root to top
Interval formula
-
Scale degrees above the root
Root frequency
-
Equal-temperament pitch (Hz)

Ready

Choose a root note and chord type, then press Find Chord.

About the Chord Finder

This tool builds a chord from a root note and a chord type using standard 12-tone equal-temperament music theory. Every chord is a set of notes stacked at fixed semitone intervals above the root within the 12-note chromatic scale (C, C#, D, D#, E, F, F#, G, G#, A, A#, B). Choose a root and a quality — major, minor, diminished, augmented, a seventh chord, or a suspended chord — and the calculator returns the note names, the interval (scale-degree) formula, and the root note's fundamental frequency in hertz.

How chord formulas work

  • Major triad: root, major 3rd (+4 semitones), perfect 5th (+7 semitones) — degrees 1-3-5.
  • Minor triad: root, minor 3rd (+3 semitones), perfect 5th (+7 semitones) — degrees 1-♭3-5.
  • Diminished triad: root, minor 3rd (+3), diminished 5th (+6) — degrees 1-♭3-♭5.
  • Augmented triad: root, major 3rd (+4), augmented 5th (+8) — degrees 1-3-♯5.
  • Seventh chords (maj7, dominant 7, m7, m7♭5, dim7) add a fourth note 9-11 semitones above the root, depending on quality.
  • Suspended chords (sus2, sus4) replace the 3rd with a major 2nd or perfect 4th, so the chord is neither major nor minor.

Reading the frequency result

The root frequency uses the standard equal-temperament formula f = 440 × 2^((n − 69) / 12), where n is the MIDI note number of the root at the octave you chose and 440 Hz is the international tuning reference for A4 (the A above middle C). Middle C is C4, MIDI note 60, at roughly 261.63 Hz.

Frequently Asked Questions

How are the notes in a chord calculated?
Each chord is built by stacking specific intervals, measured in semitones, above a root note within the 12-tone chromatic scale. A major triad, for example, uses the root, a major third (4 semitones up), and a perfect fifth (7 semitones up).
What is the difference between a major and minor chord?
Both are three-note triads sharing the same root and fifth. The only difference is the third: a major chord uses a major third (4 semitones above the root), while a minor chord uses a minor third (3 semitones above the root), which gives minor chords their darker sound.
Why does a note show as C#/Db instead of one name?
C# and Db are enharmonic equivalents — the same pitch in 12-tone equal temperament with two possible spellings depending on musical key and context. This calculator displays sharp names for simplicity; the pitch itself is identical either way.
What does the root frequency value mean?
It is the root note's fundamental frequency in hertz, calculated with the standard 12-tone equal-temperament formula f = 440 x 2^((n-69)/12), where n is the MIDI note number and A4 (440 Hz) is the tuning reference.

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