Answers to the most common questions about chord construction, interval theory, the tools on Chord-Calculator.com, and music theory concepts related to chords, progressions, and harmony.
About the Tools
What does the Chord Calculator do?
The Chord Calculator takes a root note and a chord quality as input and returns the complete chord — every note it contains, the interval each note forms with the root, and all possible inversions. The results are derived from the standard interval formulas that define each chord quality in Western tonal theory. No microphone, no audio, no estimation — every result is exact. Full technical documentation is in the How It Works page.
What does the Chord Finder do?
The Chord Finder works in reverse. You enter a set of notes and the tool identifies what chord they form — the root, quality, and inversion. It tests each note in the set as a potential root, calculates the intervals the other notes form with it, and matches the result against known chord formulas. If the notes can be named as more than one chord — as often happens with inversions or enharmonic equivalents — all valid names are returned.
Do these tools require microphone access or any audio?
No. All tools on Chord-Calculator.com are pure calculation and lookup tools. They work entirely from typed or selected input — note names, chord names, or interval inputs. No microphone access is requested, no audio is processed, and no Web Audio API is used. There is nothing to hear and nothing to listen to. Full details are in the Data Security page.
Chord Construction
What is a chord?
A chord is a combination of three or more notes sounded simultaneously or in close succession. In Western tonal music, most chords are built by stacking intervals of a third above a root note — a system called tertian harmony. The pattern of intervals used determines the chord’s quality and sound character. A major chord sounds bright and stable because of the specific interval pattern it uses. A minor chord sounds darker and more introspective because its interval pattern differs by a single semitone.
What is the difference between a major and minor chord?
Both major and minor triads contain a root, a third, and a fifth. The difference is in the third:
- Major chord: The third is a major third (4 semitones above the root). C major = C, E, G.
- Minor chord: The third is a minor third (3 semitones above the root). C minor = C, Eb, G.
The fifth is a perfect fifth (7 semitones) in both cases. The single semitone difference in the third produces a significant change in emotional character — major chords are typically described as bright, happy, or stable; minor chords as darker, more melancholic, or introspective.
What is a seventh chord and how is it different from a triad?
A seventh chord adds a fourth note — a seventh above the root — to a basic triad. The quality of the seventh (major or minor) determines the chord type:
- Major 7th (Cmaj7): Major triad + major seventh (C, E, G, B) — sophisticated, floating quality
- Dominant 7th (C7): Major triad + minor seventh (C, E, G, Bb) — tense, wants to resolve
- Minor 7th (Cm7): Minor triad + minor seventh (C, Eb, G, Bb) — smooth, jazzy quality
- Half-diminished (Cm7b5): Diminished triad + minor seventh (C, Eb, Gb, Bb) — tense, ambiguous
- Fully diminished (Cdim7): Diminished triad + diminished seventh (C, Eb, Gb, Bbb) — maximum tension
The dominant 7th is the most harmonically significant seventh chord in tonal music because its tritone interval (between the third and the seventh) creates a strong pull toward resolution.
What are extended chords — 9ths, 11ths, 13ths?
Extended chords continue stacking thirds above the seventh. A 9th adds a ninth (two semitones above the octave), an 11th adds an eleventh (five semitones above the octave), and a 13th adds a thirteenth (nine semitones above the octave). Extended chords are common in jazz and sophisticated pop harmony. In practice, not all notes are always played — arrangers and orchestrators often omit certain chord tones (particularly the 5th and sometimes the 11th) to avoid muddiness, while retaining the notes that define the chord’s identity and character.
What are altered chords?
Altered chords modify one or more of the standard chord tones by raising or lowering them by a semitone. Common alterations include: b5 (diminished fifth), #5 (augmented fifth), b9 (minor ninth), #9 (augmented ninth), #11 (augmented eleventh), and b13 (minor thirteenth). Altered dominant chords (such as C7#9 or C7b9) are particularly common in jazz, where the alterations increase harmonic tension and create more colourful resolutions. The C7#9 — sometimes called the “Hendrix chord” — contains both a major third and an augmented ninth, which is enharmonically equivalent to a minor third, creating a distinctive ambiguous quality.
Intervals
What is an interval in music theory?
An interval is the distance between two notes, measured in semitones and named according to its position in the scale. The twelve intervals within one octave range from the perfect unison (0 semitones, same note) to the perfect octave (12 semitones, same note one octave higher). Intervals are the building blocks of chords and scales — understanding intervals is the foundation of understanding all of music theory.
What is a tritone and why is it important?
The tritone is the interval of 6 semitones — exactly halfway between the unison and the octave. It can be called either an augmented fourth (A4) or a diminished fifth (d5) depending on the harmonic context. The tritone is the most dissonant interval in Western tonal music and has been called diabolus in musica (the devil in music) in historical theory. Its instability creates the tension at the heart of the dominant seventh chord — in a G7 chord resolving to C major, the tritone between B and F resolves outward to C and E (or inward to C and E depending on voice leading). This resolution drives much of tonal harmony’s sense of forward motion.
What is the difference between a major third and a minor third?
- Major third: 4 semitones. Sounds relatively open and bright.
- Minor third: 3 semitones. Sounds slightly more closed and darker.
These two intervals are the building blocks of all basic chord types. Major chords have a major third on the bottom; minor chords have a minor third. Diminished chords have two minor thirds stacked. Augmented chords have two major thirds stacked.
Inversions and Voicings
What is a chord inversion?
An inversion places a chord tone other than the root in the bass (lowest) position. A C major chord (C, E, G) in root position has C in the bass. In first inversion, E is in the bass (E, G, C). In second inversion, G is in the bass (G, C, E). The notes of the chord do not change — only their vertical arrangement. Inversions are used in voice leading to create smoother bass line movement between chords.
What is the difference between an inversion and a voicing?
An inversion specifies which chord tone is in the bass. A voicing describes how the notes are distributed across registers — how close or spread the notes are (close voicing vs open voicing), which notes are doubled, and which notes are omitted. Two chords can have the same inversion but completely different voicings. Voicing is a performance and arrangement decision; inversion is a theoretical description of the bass note.
Harmonic Function
What does it mean for a chord to “want to resolve”?
In tonal music, certain chords create harmonic tension — a sense of instability or expectation — that finds satisfaction in resolution to a more stable chord. The dominant seventh chord (V7) is the strongest example: the tritone between its third and seventh creates tension that typically resolves to the tonic chord (I). This resolution — V7 to I — is the most fundamental harmonic motion in Western tonal music and underlies an enormous proportion of classical, jazz, and popular music.
What is a chord progression?
A chord progression is a sequence of chords that creates harmonic movement through a key. Progressions are described using Roman numerals indicating each chord’s scale degree: I is the tonic (root) chord, IV is the subdominant (fourth degree), V is the dominant (fifth degree), ii is the supertonic minor, vi is the relative minor, and so on. The I–IV–V–I progression is foundational in blues, rock, and country. The ii–V–I is fundamental in jazz. Understanding Roman numeral analysis allows you to recognise the same progression in any key.
About This Website
Who runs Chord-Calculator.com?
Chord-Calculator.com is founded and maintained by Liam, a music theorist and chord tools developer. Liam researches and writes all content on the site. The site is independent and not affiliated with any music school, conservatoire, or music software company.
How do I report an error or get in touch?
Use the Contact page. For tool errors, include the root note, chord quality, and the result you believe is incorrect. For content errors, include the page URL and the specific claim. All messages are reviewed personally by Liam.
Last updated: June 2026 — Liam, Chord-Calculator.com