Chord Calculator

Musical chords are built by stacking intervals above a starting pitch known as the root note. Using the 12-tone chromatic scale, each note is assigned an integer value from 0 to 11 (starting with C as 0, C# as 1, and so on up to B as 11). A chord type defines a specific formula of semitone offsets relative to that root. For example, a standard major triad consists of the root (0 semitones), a major third (+4 semitones), and a perfect fifth (+7 semitones). By applying these modular arithmetic rules, our calculator determines the exact note names for any combination of root and harmony.

Let us walk through building a C Major chord using our calculation logic. First, set your Root Note to C and your Chord Type to Major Triad. The root note C sits at position 0 on our chromatic scale. Next, we apply the major triad interval formula of root, major third, and perfect fifth. Adding 4 semitones to C brings us to E, which forms the major third. Adding 7 semitones to C brings us to G, completing the perfect fifth. Therefore, the resulting notes for a C major chord are C, E, and G.

To get the most out of your harmonic practice, keep these essential tips in mind. First, always memorize your major and minor triads before exploring extended harmonies like 9ths and 11ths. Second, practice spelling chords in different inversions—moving the third or fifth to the bass creates entirely new emotional textures while retaining the same underlying notes. Finally, use this calculator to verify your chord spellings when writing sheet music to ensure proper enharmonic notation, such as using flats or sharps appropriately based on the key signature.