Naming what your hands already found
Players stumble onto chords constantly. A shape under the fingers sounds beautiful, or a few notes on a keyboard land together in a way that suits a melody, and then comes the practical question of what it is called. Without a name, you cannot write it on a chart, tell a bandmate, or find it again next week. This page turns the notes into a name.
There are three ways in. The piano covers two octaves, from C3 to B4, and works well for keyboard voicings and for reading a chord off sheet music. The guitar neck shows standard tuning across frets 0 to 12, accepts one note per string, and lets you mute a string you are not playing, so that you can enter a shape exactly as you hold it. The third way is a text box, where you type note names, useful when you have a chord symbol or a written voicing from a score. Example chips for C, Am, G7, C/E, Dm7 and Fmaj7 fill the notes in one tap, which is a fast way to see how the page reports a chord before you enter your own.
After you enter at least two notes, the page proposes the best name, then shows the notes of the chord as intervals above the root and the other names the same set of notes can take. A button plays the notes together so you can confirm by ear that what you entered is what you intended.
How a chord is built
A chord is a root note with other notes stacked at fixed distances above it. The distances are counted in semitones, the smallest step on a piano, and each pattern has a name. The table in the Numbers tab lists the main ones in C, from the major triad at 0-4-7 to added-ninth chords.
A major triad is root, major third (4 semitones) and perfect fifth (7). Swap the third for a minor third (3 semitones) and it becomes minor. Flatten the fifth of a minor triad to 6 and you have diminished, and raise the fifth of a major triad to 8 and you have augmented. Those four triads are the base of almost everything else.
Add a seventh and the chord gets a new color. A dominant seventh, such as G7, stacks a minor seventh (10 semitones) on a major triad and has a pull toward resolution. A major seventh uses 11 semitones and sounds smooth and open. A minor seventh puts the 10 on a minor triad and is warm and relaxed. The half-diminished, or m7b5, and the fully diminished seventh stack on top of a diminished triad.
Suspended chords replace the third with either a second (2 semitones) or a fourth (5). Without a third, they are neither major nor minor, which gives them an open, undecided sound that wants to move. Power chords drop the third altogether and keep root and fifth, and are the heart of rock guitar because they stay clear under distortion. Sixth chords add a major sixth (9) to a triad, and added-ninth chords keep the full triad and put the second degree of the scale on top of it.
Inversions and slash chords
The same three notes can be arranged in different orders. C, E and G stacked in that order, with C at the bottom, is root position. Put E at the bottom and the chord is in first inversion, with G and C above. Put G at the bottom and you have second inversion. The letters are the same, but the character shifts. Root position sounds solid and settled, and inversions lean forward and flow into the next chord.
A slash chord names the lowest note after a slash. C/E is a C chord with E in the bass, and C/G is a C chord with G in the bass. The rule in this finder is simple: the lowest note you enter decides the bass. Enter C, E and G with the E lowest and the answer comes back as C/E, and the interval list shows the notes relative to the root C.
Songwriters use slash chords to make a bass line that moves by step. A progression such as C, G/B, Am, C/G walks the bass line down in small steps over chords that otherwise skip around, and it feels smoother for it. On guitar, a slash chord often arises naturally, since a shape that leaves out the lowest string puts a different note on the bottom.
Why one set of notes can have several names
Take C, E, G and A. Treated with C as the root, they form C6, a major triad with an added sixth. Take the same four notes with A as the root: A, C, E, G is Am7, a minor triad with a minor seventh. The notes are identical, and only the choice of root changes. The finder lists both under the heading of other names, so you can pick the one that fits the key and the context.
How do you choose? Look at the bass note and the music around it. If the bass plays C and the chord resolves into F, C6 is the natural reading. If the bass plays A and the harmony moves toward D, think Am7. The sound can feel different too because the ear hears the lowest note as the foundation. Neither name is wrong; they describe the same pile of notes from different starting points.
Other pairs behave the same way. A half-diminished chord such as Cm7b5 contains the notes of Ebm6, and a diminished seventh chord is symmetrical, so each of its four notes can serve as the root. Augmented triads are symmetrical too: C+, E+ and G#+ are the same notes.
Spelling matters as well. The same black key can be written C# or Db, and which one is right depends on the key and the chord. A good rule is that a chord is spelled with one of each letter name, so a C major triad is C E G and not C Fb G. A D-flat major triad is Db F Ab, never C# E# G#. When you write a chord into a chart, check the spelling against the key you are in. The finder itself writes black keys as C#, F# and G# and as Eb, Ab and Bb, so rename them to fit your key.
Finding scales that fit
Below the name is a list of scales that contain every note you entered. This answers a question that comes right after naming a chord: what can I play over it? If a scale holds all the chord tones, then its other notes are safe choices for a melody or solo over that chord.
The notes C, E, G and A fit the C major scale, the F major scale and the G major scale, as well as A natural minor and a couple of pentatonic collections. This is useful because it also tells you which keys the chord belongs to. A chord that fits only one or two scales strongly implies a key, and one that fits many, like a plain major triad, can live in many places.
A chord with notes outside the usual diatonic scales, such as a diminished seventh or an augmented triad, will match fewer major or minor scales and may only appear in symmetric scales or in harmonic minor. That is a sign that the chord is a passing color rather than a home base.
Finding chords for a melody
People often ask how to find chords for a melody they have in their head or on a page. The method works in a few steps and the finder helps with each of them.
First decide the key. Look at the melody notes and find the major or minor scale that holds all of them. The tonic, the note that feels like home, is usually where the melody ends. Second, build the triads of that scale: in a major key, the chords on degrees one to seven are major, minor, minor, major, major, minor and diminished. In C that is C, Dm, Em, F, G, Am and Bdim. These seven are your candidate pool.
Third, go through the melody a bar at a time. The notes that fall on strong beats or are held the longest are the ones that matter most. For each bar, pick the chord from your pool that contains the most of them. A melody that circles around C, E and G wants a C chord, and one that lands on D and F wants Dm or G7. Type the notes into the finder to see which chords include them and compare the candidates.
Finally, listen. Play the chord and the melody together. Two chords may both fit on paper, and one will simply sound better. Common progressions, such as I, V, vi, IV, give you a place to start, and any change you make by ear is a good one if it sounds right to you.
Guitar notes and frets
The guitar view assumes standard tuning, E A D G B E. Frets are numbered 0, the open string, up to 12, where the pattern starts again an octave higher. Click a position to place a note on that string, and use mute for any string you do not play. Because only one note can sound per string, you can enter any normal chord shape without confusion, including barre chords and open voicings.
On a guitar, the same pitch exists in several places. The A above middle C can be found on the high E string at the fifth fret or on the B string at the tenth, for example, so shapes with the same notes can be played in more than one position. Sort these out by entering the shape you hold; the page names the notes, not the fingering.
Notes you enter are processed in the page and played with a simple synthesized tone. They are not sent anywhere.
Frequently asked questions
How do I identify a chord?
List the notes, find which one is the root, and measure the other notes above it in semitones. A pattern of 0, 4, 7 is major; 0, 3, 7 is minor. Or skip the arithmetic: click or type the notes in the finder and it returns the name, the intervals and other names.
How do I find a chord for a song?
Work out the key, then try the chords built on each note of that key's scale. Listen for the bass note on the first beat of a bar and compare it with the melody. If you can play a few notes together by ear, enter them here to confirm the name of what you found.
How do I find a chord progression for a melody?
Identify the key from the melody notes, then choose chords from that key that contain the melody notes on strong beats. Start with common patterns such as I, vi, IV, V, and test each bar by ear. The finder helps by showing which chords contain a given group of notes.
Which guitar scales should I learn first?
The minor pentatonic is the usual first choice. It has five notes per octave, fits easily under the fingers, and works in rock, blues and pop. Next come the major scale and the major pentatonic. After those, the natural minor scale and the modes make sense, and the finder shows which scales hold your chord.
Why does the same chord have two names?
Because the name depends on which note you treat as the root. C, E, G and A are C6 when counted from C and Am7 when counted from A. The notes do not change. The bass note and the surrounding chords usually show which name is the better description in a given song.
What does a slash chord like C/E mean?
The letter before the slash is the chord and the letter after it is the lowest note. C/E is a C major chord with E in the bass, which is the first inversion. It is often used to make a bass line move smoothly from one chord to the next.