How Cadences Work: Authentic, Plagal, Half and Deceptive

A cadence is a short chord pattern that closes a phrase, much as punctuation closes a sentence. When you hear a song pause, settle, or leave a question hanging, you are usually hearing a cadence. Composers in the common-practice period used a small set of standard cadences, and each one signals a different degree of finality. Knowing the set gives you a practical way to hear where a phrase ends and how strongly it ends.

This guide covers the four cadences you will meet most often: the authentic, the half, the plagal and the deceptive. It also covers the perfect and imperfect forms of the authentic cadence, because the difference between them matters just as much in practice. All examples use C major, so you can check each one on a keyboard.

What makes a cadence

A cadence needs two things: a pair of chords and a sense of where the phrase stops. The chords carry the harmonic function, and the melody and bass show how final the stop feels. Most cadences use the dominant (V) or the subdominant (IV) as the approach chord and the tonic (I) as the goal, or they stop on the dominant without resolving at all.

Think of the dominant as a chord that creates tension and wants to move home. The tonic is the chord that releases that tension. A cadence is simply the moment where that tension is either released, delayed, or redirected. The stronger the release, the more final the ending sounds.

The authentic cadence

The authentic cadence moves from V to I. In C major that is G to C. It is the strongest and most common cadence in tonal music, and it is what most listeners expect when a piece says goodbye.

Authentic cadences come in two strengths, and the difference lies in how the chords are arranged:

Type	Chord motion	Top note of tonic chord	Bass on tonic	Closure
Perfect authentic (PAC)	V to I, both in root position	Tonic (C)	Yes	Full stop
Imperfect authentic (IAC)	V to I, inverted or non-root position	Mediant or dominant	Not always	Weaker stop

A perfect authentic cadence needs three conditions: both chords in root position, the tonic note on top, and the tonic in the bass. Remove one condition and the ending still sounds like a close, but it feels less conclusive. A common example is a V6 chord moving to I. The V6 chord has B in the bass rather than G, so the bass rises to C instead of falling a fifth. That sounds like a pause rather than the end of a piece.

The half cadence

The half cadence ends on the dominant. Any chord can lead into it, so in C major you might hear C to G, or F to G, or Am to G. The phrase stops on G and leaves the listener waiting for a continuation.

Because it sounds unfinished, the half cadence often closes the first phrase of a period. The answering phrase then ends with an authentic cadence. This pairing is the basis of the antecedent and consequent structure you will find in many folk tunes and classical themes. The half cadence works like a question mark, and the authentic cadence that follows works like the answer.

The plagal cadence

The plagal cadence moves from IV to I, which in C major is F to C. Musicians often call it the Amen cadence because it closes many hymns, where the final word is sung over this chord pair. It feels gentle and calm compared with the authentic cadence.

Plagal endings are common in hymns, church music, and popular songs that want a soft, reflective close. Plenty of pop and gospel endings use a repeated IV to I figure for exactly this reason. The IV chord does not pull as hard toward the tonic as V does, so the resolution feels like settling down rather than snapping shut.

The deceptive cadence

The deceptive cadence sets up a V to I motion and then swaps the expected tonic for another chord. The most common version is V to vi. In C major that is G to Am. The leading tone still rises to C in the upper voice, so the ear recognises the approach, but the bass lands on A instead of C.

Composers use the deceptive cadence to extend a phrase without closing it, to add a moment of drama, or to slip into a new section. Because it dodges the expected release, it is usually weaker than the authentic cadence in terms of finality. Listeners often hear it as a turn rather than an ending.

Other cadence names you may see

Textbooks use several other labels. The phrygian half cadence, found mostly in minor keys, moves from a iv6 chord to V, as in Dm6 to E in A minor. Its sound is sharp and old-fashioned, and Baroque composers used it often.

Comparing the four cadences

The table below ranks the main cadences by how final they sound and gives a typical use for each one.

Cadence	Motion in C major	Closure	Typical role
Perfect authentic	G to C (root position)	Strongest	Final ending
Imperfect authentic	G to C (inverted)	Strong but softer	Mid-piece pause
Plagal	F to C	Gentle	Hymn-like close
Half	Any chord to G	Open	Question, first phrase
Deceptive	G to Am	Weak	Surprise, extension

Use this table as a quick reference when you analyse a song. Listen first for the strongest closure, then work backward to see where the piece stops, pauses, or surprises you.

Hearing cadences in practice

To train your ear, play a simple melody in C major and end it on different chords. Start with G to C to hear the perfect authentic cadence. Then end on G alone to hear the half cadence. Try F to C for the plagal, and G to Am for the deceptive. Repeat each example several times until you can name the feeling without looking at the chords.

Most songs contain several cadences. Verses often end with a half or imperfect authentic cadence, while the final chorus usually closes with a perfect authentic or plagal ending. Once you can spot these, you will find that the form of a piece becomes much easier to follow.

Why cadences matter for composers

Cadences are the main tool composers use to shape time. They tell listeners where a section begins and ends, where a surprise is coming, and how much energy remains. A writer who understands cadences can control the pace of a song without changing the tempo at all. Placing a half cadence at the right moment makes the listener want the next phrase, while a well-timed perfect authentic cadence gives a sense of arrival that no other device can match.

Key takeaways

The authentic cadence moves from V to I and gives the strongest close. Its perfect form needs root position chords and the tonic on top. The half cadence stops on V and leaves a question open. The plagal cadence moves from IV to I and feels calm. The deceptive cadence swaps the expected tonic for vi and creates surprise.

Learn these four patterns by ear, and you will hear the structure of tonal music more clearly. Start with short melodies, identify the last two chords, and name the cadence before you check your answer.