Chords Explained: How Every Chord Is Built

Open any chord chart, method book, or lead sheet and you'll eventually run into a symbol that doesn't mean anything to you yet — maybe it's Dm7b5, maybe it's Gsus4, maybe it's just a plain F that refuses to ring cleanly no matter how you place your fingers. Almost every one of those moments has the same underlying cause: the symbol is describing a small, mechanical recipe, and once you know the recipe, the symbol stops being a mystery. This guide is the long-form version of that recipe, walked through once, in full, with real chords from this site's own guitar, piano, and ukulele libraries used as concrete examples rather than abstract letters.

Start With Three Notes

Almost every chord on this site starts life as a triad — three notes, built by choosing a root and stacking two more notes a third above each other on top of it. A third is just the musical distance spanning three letter names; C up to E is a third (skipping D), and E up to G is another third (skipping F). Stack a bigger third first and a smaller one second and you get a major triad; reverse that order and you get a minor triad instead. The C major chord and C minor chord pages on this site show exactly this pair side by side — same root, same outer span between the lowest and highest note, one different note in the middle deciding the entire emotional character.

Two rarer triads round out the full set of four possibilities. Stack two small thirds in a row and the top note lands slightly short of where a triad "expects" it, producing the unstable, unresolved sound of a diminished triad — the C diminished chord page on the piano section shows this shape directly on a keyboard, where the compressed spacing between all three keys is easy to see at a glance. Stack two big thirds in a row instead and you overshoot in the other direction, producing an augmented triad, documented on this site's C augmented page — a chord so genuinely rare in ordinary pop and folk writing that most guitarists encounter it first as a curiosity rather than a chord they reach for by habit.

Adding a Fourth Note

Once a triad exists, the next move is almost always the same one: stack one more third on top. Do that to a major triad using a smaller third and you get a dominant seventh chord, the workhorse of blues, folk, and a huge share of pop harmony — the C7 chord page documents this shape on guitar, and it's worth comparing directly against the C major triad it's built from to see exactly which one note was added. Use a bigger third on top of that same major triad instead and you get a major seventh chord (Cmaj7), a noticeably smoother, more "jazzy" sound built from the identical starting triad with just one different choice at the final step. Stack a small third on top of a minor triad and you land on a minor seventh (Cm7), and this site's guitar, piano, and ukulele Cm7 pages each show how differently that identical set of notes gets physically arranged depending on the instrument in your hands.

The Chords That Break the Rule

Two whole families of chord deliberately step outside the stack-a-third pattern, and they're genuinely worth knowing as exceptions rather than confusing variations on the main rule. Suspended chords swap out the third entirely — the very note that decides major versus minor — for a second or a fourth instead, which is exactly why a sus chord sounds neither happy nor sad, just unresolved, hanging in midair until it moves somewhere else. The C sus2 and C sus4 chord pages on this site show both replacement notes side by side against the same C root. Power chords go a different direction and simply drop the third altogether, leaving a bare root and fifth with no major/minor quality at all — a shape guitarists reach for constantly in rock and metal specifically because removing the third also removes any harmonic "opinion" the chord would otherwise carry, something covered in full on this site's Power Chords Explained theory page.

Stretching Past the Seventh

Extended chords keep the exact same stacking process going past the seventh, adding a ninth, an eleventh, or a thirteenth by continuing to pile thirds upward. Because these notes eventually climb past a full octave above the root, they get renamed relative to where they land rather than counted as a ninth, tenth, eleventh straight through — a 9th is really a 2nd an octave up, an 11th is really a 4th an octave up, and this site's Chord Extensions theory page walks through exactly why that renaming happens and how it connects back to the underlying scale. On guitar, a full C13 chord asks for more notes than six strings and four fingers can realistically supply at once, so this site's C13 guitar page documents the specific compromise voicing players actually use — a small, practical detail extended-chord theory alone doesn't tell you, but the fingering diagram makes obvious immediately.

Reordering: Inversions

Every chord discussed so far has been shown in root position, meaning the root sits as the lowest-sounding note. Slide a different chord tone into the bass instead — the third, the fifth, sometimes an extension — and you get an inversion: the identical set of notes, rearranged, producing a smoother bass line when moving between chords and often changing how "settled" or "in motion" a progression feels. This site's Chord Inversions theory page covers the mechanics in depth, including why a first-inversion chord is written with a slash (C/E, meaning a C major chord with E, not C, as the lowest note).

Same Chord, Three Different Instruments

A C major chord is the identical three notes — C, E, G — no matter which instrument plays it, but the physical shape that produces those notes looks nothing alike across guitar, piano, and ukulele, and comparing the three side by side is one of the fastest ways to understand why this site documents every chord separately per instrument rather than once. On piano, C major is about as simple as a chord gets: three adjacent-ish white keys, no black keys involved, played with three fingers in a single hand position. On guitar, standard tuning (EADGBE) means the open C major shape spreads those same three notes across five strings with some notes doubled an octave apart, fretted with three fingers in an asymmetric shape that has nothing visually in common with the piano version — Guitar Tuning Explained covers why the instrument's specific string intervals produce that spread. On ukulele, reentrant tuning (the high-strung G string sitting above, not below, the C string) means the identical C major chord collapses into arguably the easiest shape on the entire instrument — a single finger on one string — precisely because of a tuning quirk this site's Ukulele Reentrant Tuning Explained page walks through directly.

Chords Come From Scales

None of the chord construction covered above happens in a vacuum — every triad, seventh, and extension on this site's roster is built from notes that also exist inside a scale, and the two systems are really one system viewed from different angles. The C major scale, documented on its own dedicated scales page, contains every note the C major, C7, Cmaj7, and every diatonic chord in the key of C draws from; stack thirds starting on each of that scale's seven notes in turn and you get that key's full set of diatonic chords — the exact process the Diatonic Chords theory page walks through directly. The relationship runs the other way too: the C minor pentatonic scale, a five-note subset that deliberately omits the two notes most likely to clash awkwardly against a minor chord, is exactly why it's the first scale so many guitarists reach for when improvising over a minor-key progression — a genuine structural reason, not just tradition, covered on this site's own pentatonic scale pages and explained further in a companion post on this blog about why pentatonic scales are usually the first scale guitarists learn.

From One Chord to a Real Progression

Understanding a single chord's construction is the foundation, but chords rarely appear alone — they move from one to the next in a progression, and which chord follows which isn't random. The Chord Progressions and Chord Function theory pages on this site cover how chords built on different scale degrees serve different roles (a stable "home base" tonic, a chord that creates tension, a chord that pulls strongly back toward resolution), and a companion post on this blog walks through the specific progressions that show up over and over across genres for exactly that functional reason. Once a progression is chosen, moving it into a more comfortable key for a singer or another instrument is a matter of shifting every chord's root by the same interval while keeping each chord's quality untouched — the manual method is covered in another post on this blog, and this site's Transposer tool automates the identical calculation instantly.

A Genuinely Common Source of Confusion: Enharmonic Chords

One detail worth clearing up directly, since it trips up a lot of players moving between chord charts written by different people: the same chord can sometimes be spelled two different ways depending on context — C# major and Db major describe the identical set of pitches, just named differently depending on which spelling fits the surrounding key more cleanly. This site's C sharp major chord page documents that shape under the sharp spelling specifically because either spelling might show up on a real chart depending on the key that chord is functioning in, and recognizing that the two names aren't actually two different chords is worth internalizing early rather than treating it as a separate memorization problem.

Reading an Unfamiliar Symbol Without Panicking

A genuinely useful skill this whole guide is really building toward: the ability to look at an unfamiliar chord symbol — something like Ebm7b5, or Gadd9 — and work out what it means on the spot rather than needing to look it up. Start with the letter (the root), then read the quality markers left to right in the order they appear. "m" or "min" means start from a minor triad rather than major; "7" stacks a seventh on top, with the specific type (dominant, major, minor, half-diminished) determined by what precedes it; "add9" means a plain triad with a ninth added on top, deliberately skipping the seventh that a plain "9" symbol would imply — a genuinely common point of confusion covered directly on this site's Chord Extensions theory page, since "add9" and "9" look similar but describe different chords. Practicing this kind of on-the-spot decoding with a handful of real chord symbols from this site's own guitar, piano, and ukulele libraries is a faster way to build real fluency than trying to memorize every possible symbol combination in advance.

Where to Go From Here

If everything above feels like a lot to hold at once, that's normal, and it's exactly why this site is organized the way it is: every chord mentioned here has its own dedicated page, with a real diagram, fingering, and written explanation, reachable from the guitar, piano, and ukulele hub pages. The Chord Finder tool lets you go the other direction — enter notes or a shape you've found by ear and get the matching chord name back — and the Scale Visualizer and Progression Builder tools turn the scale and progression concepts covered above into something you can see and hear directly on a virtual fretboard or keyboard rather than only read about. This site's Tuner and Metronome tools round out the practical side of things once a chord or progression is chosen: a chord fretted perfectly but played on an out-of-tune instrument still sounds wrong, and a progression practiced without a steady beat rarely translates cleanly into confident playing alongside other musicians. There's no required order to learn any of this in beyond curiosity: start with whichever chord is stumping you today, follow the mentions this guide points toward, and the rest of the system tends to fill in around it faster than tackling it all at once from the front.