Chord Calculator: Notes, Formula, and Intervals for Any Chord
Select a root note and chord type to instantly see every note in the chord, its interval formula, and how many semitones each note sits above the root. Covers 19 chord types across all 12 keys, from simple triads and power chords to extended 9th chords. The steps panel walks through the construction so you understand the theory, not just the answer.
How chords are built
Every chord starts from a root note and adds other notes at specific intervals above it. Those intervals are measured in semitones, the smallest step on a standard keyboard (one fret on a guitar). A major triad, for example, adds a note 4 semitones above the root (a major third) and another 7 semitones above the root (a perfect fifth). On C, that gives C, E, and G. A minor triad lowers the middle note by one semitone: C, Eb, G. The quality of a chord (its brightness or darkness) comes entirely from which intervals appear. Extended chords (7ths, 9ths) add more notes further up the same pattern.
Understanding the interval formula
Chord formulas are written as scale degrees relative to the major scale of the root. Degree 1 is the root, 3 is the major third, 5 is the perfect fifth, 7 is the major seventh. A flat symbol (b) lowers a degree by one semitone, a sharp (#) raises it by one. So a minor chord formula is 1 - b3 - 5: root, flattened third, perfect fifth. A dominant 7th is 1 - 3 - 5 - b7: a major triad with a flattened seventh on top. The double flat (bb7) in the diminished 7th formula lowers the 7th by two semitones, landing it only three semitones above the flattened fifth. Once you can read the formula, you can construct any chord in any key without memorising separate note lists.
Triads, 7th chords, and extended chords
Chords fall into three families by how many notes they contain. Triads (3 notes) are the starting point: major, minor, augmented, diminished, and suspended (sus2, sus4). They give harmony with the least clutter and are the right choice for most song accompaniment. 7th chords add a fourth note a seventh above the root. The dominant 7th is the workhorse of blues and jazz, the major 7th adds a dreamy quality used in pop and bossa nova, and the minor 7th sits at the heart of jazz voicings and neo-soul. Extended chords go further: 9th chords add the ninth (the same pitch as the second, one octave higher). They create a richer, fuller sound but take more fingers and can easily muddy a guitar or vocal arrangement if over-used. The add9 chord keeps the 9th without the 7th, giving color without the jazz weight.
Enharmonic spelling and flat vs sharp roots
Many notes have two names: C# and Db are the same pitch (one semitone above C) but spelled differently depending on the musical context. This calculator uses the most common convention: keys with flat key signatures (F, Bb, Eb, Ab, Db, Gb) spell their chord notes with flats, while all other keys use sharps. That is why an Eb major chord shows Eb, G, Bb rather than D#, G, A#. Both are technically correct for the underlying pitches, but the flat spelling matches standard notation in those keys and is easier to read. If you see a note spelled as Cb, it is the same pitch as B; if you see Fb, it equals E. These appear in some diminished and augmented chords and are theoretically correct even though they look unusual.
Chord types: formula, semitones, and sound
| Chord type | Symbol | Formula (degrees) | Semitones from root | Character |
|---|---|---|---|---|
| Major triad | 1 - 3 - 5 | 0 - 4 - 7 | Bright, stable | |
| Minor triad | m | 1 - b3 - 5 | 0 - 3 - 7 | Dark, melancholic |
| Augmented triad | aug | 1 - 3 - #5 | 0 - 4 - 8 | Tense, unsettled |
| Diminished triad | dim | 1 - b3 - b5 | 0 - 3 - 6 | Very tense |
| Suspended 2nd | sus2 | 1 - 2 - 5 | 0 - 2 - 7 | Open, airy |
| Suspended 4th | sus4 | 1 - 4 - 5 | 0 - 5 - 7 | Uplifting suspense |
| Dominant 7th | 7 | 1 - 3 - 5 - b7 | 0 - 4 - 7 - 10 | Bluesy pull |
| Major 7th | maj7 | 1 - 3 - 5 - 7 | 0 - 4 - 7 - 11 | Lush, dreamy |
| Minor 7th | m7 | 1 - b3 - 5 - b7 | 0 - 3 - 7 - 10 | Cool, smooth |
| Minor-major 7th | mMaj7 | 1 - b3 - 5 - 7 | 0 - 3 - 7 - 11 | Dramatic |
| Diminished 7th | dim7 | 1 - b3 - b5 - bb7 | 0 - 3 - 6 - 9 | Highly dissonant |
| Half-diminished 7th | m7b5 | 1 - b3 - b5 - b7 | 0 - 3 - 6 - 10 | Sophisticated |
| Major 6th | 6 | 1 - 3 - 5 - 6 | 0 - 4 - 7 - 9 | Warm, complete |
| Minor 6th | m6 | 1 - b3 - 5 - 6 | 0 - 3 - 7 - 9 | Bittersweet |
| Dominant 9th | 9 | 1 - 3 - 5 - b7 - 9 | 0 - 4 - 7 - 10 - 14 | Rich, jazzy |
| Major 9th | maj9 | 1 - 3 - 5 - 7 - 9 | 0 - 4 - 7 - 11 - 14 | Ethereal |
| Minor 9th | m9 | 1 - b3 - 5 - b7 - 9 | 0 - 3 - 7 - 10 - 14 | Deep, emotional |
| Added 9th | add9 | 1 - 3 - 5 - 9 | 0 - 4 - 7 - 14 | Colorful, bright |
| Power chord | 5 | 1 - 5 | 0 - 7 | Strong, neutral |
All 19 chord types supported by this calculator, with their interval formulas and typical uses.
Frequently asked questions
What is a chord in music?
A chord is a set of two or more notes played at the same time (or in quick succession, which is called an arpeggio). Most chords in Western music contain three or four distinct pitches. The choice of pitches, defined by the intervals between them, determines whether the chord sounds major (bright), minor (dark), dominant (tense), or one of many other qualities.
How do I find the notes in any chord?
Identify the root note and the chord type, then apply the interval formula. A major triad uses intervals of 0, 4, and 7 semitones. Add those values to the root on the chromatic scale (C=0, C#=1, D=2, Eb=3, E=4, F=5, F#=6, G=7, Ab=8, A=9, Bb=10, B=11). For G major: 7+0=G, 7+4=11=B, 7+7=14 mod 12=2=D. Result: G, B, D. This calculator does all of that automatically for 19 chord types in all 12 keys.
What is the difference between a major and minor chord?
Both are three-note triads with a root and a perfect fifth, but the middle note differs by one semitone. A major chord has a major third (4 semitones above the root), giving a bright, happy sound. A minor chord has a minor third (3 semitones above the root), giving a darker, more melancholic sound. On piano, C major is C-E-G and C minor is C-Eb-G.
What is a dominant 7th chord and why is it special?
A dominant 7th chord (symbol: 7, e.g. G7) is a major triad with a flattened 7th on top: 1 - 3 - 5 - b7. The tension between the major 3rd and the flat 7th creates a strong pull toward resolution on the chord a fourth higher (or a fifth lower). G7 naturally resolves to C major. This makes the dominant 7th the most harmonically active chord in Western music and the backbone of blues, jazz, and classical cadences.
What is the difference between a 7th chord and an add9 chord?
A 7th chord adds the 7th scale degree on top of a triad (e.g. Cmaj7 = C-E-G-B). An add9 chord adds the 9th scale degree (the same pitch as the 2nd, one octave higher) without including the 7th. Cadd9 = C-E-G-D. The add9 keeps the sound simpler and brighter than a full 9th chord, which includes both the 7th and the 9th.
What is a suspended chord?
A suspended chord (sus2 or sus4) replaces the 3rd with either the 2nd (sus2) or the 4th (sus4). Without a 3rd, the chord has no major or minor quality, giving it an open, floating sound. Sus4 chords in particular have a natural pull back to the major chord of the same root. Csus4 (C-F-G) resolves easily to C major (C-E-G).
How are power chords different from regular chords?
A power chord contains only two pitches: the root and the perfect fifth (7 semitones up), with no 3rd. That means it is neither major nor minor. Power chords work well with heavy guitar distortion because the 3rd creates dissonant overtones when distorted, while root-plus-fifth stays clean. They are written with a 5 suffix (G5, A5, E5) and are the cornerstone of rock and metal rhythm guitar.
Why do some notes have two names (like C# and Db)?
C# and Db are the same pitch played on a keyboard or guitar (enharmonic equivalents), but the name used depends on the musical context. In keys with sharps (G, D, A, E, B), notes are spelled with sharps. In keys with flats (F, Bb, Eb, Ab, Db, Gb), notes are spelled with flats. This calculator automatically uses the spelling that matches the tonal context of the root you select.