Chord Finder: The Complete Guide
Every chord, in every key, is built from the same handful of interval formulas. This tool lets you pick any root note and chord type and instantly see its exact notes, its intervals relative to the root, a highlighted piano diagram, and a suggested guitar fingering — all calculated on the fly rather than pulled from a fixed lookup table.
How does this chord finder work?
Every chord type is defined as a formula of intervals measured in semitones above its root — a major chord, for instance, is always the root, a note four semitones above it, and a note seven semitones above that, regardless of which root you start from. This tool applies that formula to whichever root note you select, converts the resulting semitone positions into actual note names, and then maps those notes onto a piano keyboard and a guitar fretboard using standard tuning.
How to Use the Chord Finder
- Pick a root note from the twelve chips at the top — this is the note the chord is built from and named after.
- Choose a chord type, such as Major, Minor, Dominant 7, or Sus4, from the second row of chips.
- Read the chord name and notes shown below — each note chip also shows its interval label, like "3" for a major third or "b7" for a minor seventh.
- Check the piano diagram to see exactly which keys make up the chord, with the root marked distinctly.
- Try the suggested guitar fingering as a starting point, keeping in mind it's one of several valid ways to play any given chord.
Common Chord Formulas
These interval formulas work identically for any root note — apply them to C, apply them to F#, and the shape of the chord relative to its root stays exactly the same:
| Chord Type | Formula | Example (root C) |
|---|---|---|
| Major | R, 3, 5 | C, E, G |
| Minor | R, b3, 5 | C, Eb, G |
| Dominant 7 | R, 3, 5, b7 | C, E, G, Bb |
| Major 7 | R, 3, 5, 7 | C, E, G, B |
| Minor 7 | R, b3, 5, b7 | C, Eb, G, Bb |
| Diminished | R, b3, b5 | C, Eb, Gb |
| Augmented | R, 3, #5 | C, E, G# |
| Sus2 | R, 2, 5 | C, D, G |
| Sus4 | R, 4, 5 | C, F, G |
Notes vs. Intervals: Why Both Matter
A chord's notes tell you exactly what to play in a specific key — C, E, and G for a C major chord. Its intervals describe the same chord in relative terms — root, major third, perfect fifth — that hold true in every key. Thinking in intervals is what lets a guitarist or pianist transpose a song to a new key without relearning the shapes from scratch, and it's why this tool shows both side by side: the notes for what to play right now, and the intervals for the pattern underneath it.
Reading the Suggested Guitar Fingering
The guitar diagram searches each of the six strings, in standard EADGBE tuning, for the lowest fret near the open position that lands on one of the chord's notes. This produces a genuinely playable voicing for most common chords, but it's an algorithmic suggestion rather than a hand-curated "textbook" shape — some strings may show an × when no chord tone falls within that string's first few frets, which simply means that string is best left muted or unplayed for this particular voicing. Many real-world chord shapes intentionally use fewer than six strings for exactly this reason.
Common Chord-Finding Questions
Why does the same chord look different in songbooks?
Most chords can be played in multiple positions and voicings across an instrument's full range — a C major chord played as an open-position shape near the nut and a C major barre chord higher up the neck contain the same three notes but are physically different shapes. This tool shows one reasonable voicing near the open position; it isn't the only correct answer.
What does "add9" mean versus "9"?
A 9 chord includes the interval stack of a dominant 7 chord plus a 9th on top (root, 3rd, 5th, b7th, 9th). An add9 chord skips the 7th entirely and simply adds the 9th to a plain major triad (root, 3rd, 5th, 9th) — the "add" signals that the 7th is deliberately left out.
Frequently Asked Questions
Is this chord finder free to use?
Yes. This chord finder is completely free, runs in your browser, and does not require an account, download, or app install.
How is a chord's notes calculated?
Every chord is built from a formula of intervals measured in semitones above its root note. A major chord, for example, is the root, a major third four semitones above it, and a perfect fifth seven semitones above it. Applying the same formula to any root note produces that chord in every key.
Why are some guitar strings muted (X) in the suggested fingering?
The suggested fingering searches only the first few frets near the open position on each string. If that string doesn't happen to pass through one of the chord's notes within that range, it's marked muted rather than forcing an incorrect note, since many chords are genuinely played on fewer than six strings.
What is the difference between a chord's notes and its intervals?
The notes are the actual pitches in a specific key, such as C, E, and G. The intervals describe the same chord in relative terms, such as root, major third, and perfect fifth, which stay the same in every key and make it easier to see how chord types relate to each other.
All chord data is calculated locally in your browser from standard interval formulas — nothing is looked up from an external server.