A chord progression is a sequence of chords played one after another. Chords on their own are static - a progression gives them direction.
A progression is more than a list of chord names. Rhythm, bass movement, voicing, and the point where the loop restarts all affect how the sequence is heard.
Chords from a scale
Every major scale gives you seven chords built from its notes. These are called diatonic chords - the notes available within that key.
Diatonic chords in C major
Roman numerals label each chord by its position in the scale. Uppercase = major. Lowercase = minor. This system lets you talk about progressions in any key - the numbers stay the same.
Hear each diatonic chord
These are all the chords available in the key of C major. Tap each one.
Try it
Choose I, IV, and V from the chart and write their chord names in C major. Then move the same Roman numerals to G major. The chord names change, but the functional pattern stays I - IV - V.
Roman numerals describe a chord's position in the key, so the pattern can travel without rewriting the musical idea.
What makes a progression work
Good progressions create a sense of tension and release. Some chords feel stable (I), some feel tense (V), and some feel like they're pointing away from the tonic (IV, ii). Their order controls where the phrase feels settled and where it continues into the next chord.
A progression that ends on I usually sounds more final than one that stops on V. That expectation can be useful, but loop length, melody, rhythm, and production can make the same chords feel open rather than conclusive.
Key takeaway
A progression is chords in sequence. Each key gives you 7 diatonic chords within the key. Roman numerals describe them by position so they work in any key.
Next: the specific progressions that thousands of songs are built on.
Explore progressions in any key
The Harmonic Map lets you browse theory-led progressions and audition them quickly.