Iambic pentameter is a line of verse made of five iambs, pairs of syllables in which an unstressed syllable is followed by a stressed one: da-DUM da-DUM da-DUM da-DUM da-DUM.
It is the meter of almost all of Shakespeare’s sonnets and of most of the verse in his plays, and once you can hear it, the rhythm becomes a guide to where the emphasis in a line falls and why.
At a Glance
Here are the key facts about iambic pentameter for quick reference.
What Is an Iamb?
An iamb is the basic unit, or foot, of iambic pentameter: two syllables, the first unstressed and the second stressed. Many everyday English words are iambs on their own: a-LONE, be-CAUSE, to-DAY, re-TURN, a-BOVE. Iambs also form naturally across short words, as in “the CAT” or “to GO.” Because English falls into this rhythm so easily, iambic verse can sound close to ordinary speech.
“Pentameter” means five measures. Five iambs in a row make one line of iambic pentameter, ten syllables in all. It is one of the most widely used meters in English poetry, with roots going back to Chaucer, and English playwrights of the 1580s, above all Christopher Marlowe, made its unrhymed form, blank verse, the standard language of the stage.
How to Spot Iambic Pentameter
You can usually tell whether a line is iambic pentameter in five quick steps.
If a line passes these steps, it is iambic pentameter, even if it is not perfectly regular. Very few of Shakespeare’s lines are.
How to Scan a Line
Scanning a line, or scansion, means marking its stressed and unstressed syllables to see its rhythm. It is a way of listening, not an exact science, and two careful readers can scan the same line differently.
Start by reading the line aloud at a natural pace. Mark the syllables that carry weight, then divide the line into feet of two syllables each. Here is the first line of Sonnet 18, with stressed syllables in capitals and feet divided by vertical bars:
shall I | com PARE | thee TO | a SUM | mer’s DAY
Two things are worth noticing. First, “to” and “a” are not words anyone would stress in conversation, yet the meter gives them a light beat. Weak words often take the stressed position in a foot, and a good reader lets them sit there lightly rather than hitting them hard. Second, the opening can also be heard as “SHALL i,” with the stress first. Both readings are defensible, which is normal: scansion shows the pattern the line is built on, and a reader decides how closely to follow it.
The table below scans ten well-known lines, from perfectly regular ones to lines that bend the pattern.
The Main Variations
Perfectly regular lines are the exception in Shakespeare. He varies the pattern constantly, and the variations are where the meter starts to carry meaning.
Trochaic Inversion
A trochee reverses the iamb: stressed, then unstressed (DUM-da). Swapping one in for an iamb is the most common variation in English verse, and it usually happens at the start of a line or just after a pause. “NOW is the winter of our discontent” opens Richard III with a stress on its first word, so Richard’s first speech begins with a jolt. The same thing happens mid-line in Sonnet 116, where “LOVE is not love” restarts the line after a full stop.
Feminine Ending
A feminine ending adds an unstressed syllable after the last stress, giving the line eleven syllables. “To be, or not to be, that is the question” ends on the unstressed “-tion.” Feminine endings make a line land softly rather than firmly. Shakespeare used them more and more as his career went on, and his late plays have far more of them than his early ones, a pattern scholars have used to help date the plays. In the sonnets, Sonnet 20 uses feminine rhymes in all fourteen lines, and Sonnet 87 in almost all of them.
Caesura
A caesura is a pause inside a line, usually marked by punctuation. It does not change the syllable count, but it breaks the flow. “To be, or not to be, that is the question” pauses twice before it reaches its end. In Sonnet 116, the full stop after “impediments” splits line 2 in two and sets up the definition that follows.
Enjambment
Enjambment is the opposite: the sense runs past the end of a line without a pause. Macbeth’s soliloquy in Act 1, Scene 7 runs across line endings again and again: “if th’ assassination / Could trammel up the consequence, and catch / With his surcease success.” The sentences refuse to stop where the lines do, and the speech sounds like a mind racing ahead of itself. A line that does pause at its end is called end-stopped.
Elision
Some words lose a syllable in verse to fit the meter. “Heaven,” “spirit,” and “even” are often said as one syllable, and “over” is often printed as “o’er.” Apostrophes in older texts, as in “th’ assassination” above, often mark a syllable being dropped. The reverse also happens: “stretchèd” in Sonnet 17 is sounded as two syllables. When a line seems to have one syllable too many or too few, elision or its reverse is usually the reason.
Shared Lines
In the plays, one line of pentameter is sometimes split between two or more speakers. In Macbeth, just after the murder of Duncan, four short speeches make up a single line: “Did not you speak?” “When?” “Now.” “As I descended?” Together they fill out the meter, and the quick exchange shows two frightened people finishing each other’s line.
Iambic Pentameter in the Sonnets
All but one of Shakespeare’s 154 sonnets are written in iambic pentameter. The exception is Sonnet 145, which uses shorter lines of four beats, iambic tetrameter: “Those lips that Love’s own hand did make.”
In the sonnets, the meter works together with rhyme. Each Shakespearean sonnet rhymes ABAB CDCD EFEF GG, so the rhymes close off each quatrain and the couplet closes off the poem, while the meter keeps each line moving forward. Because a sonnet is only fourteen lines long, its variations are easy to track. Scanning a single sonnet line by line is one of the best ways to train your ear, and the variations often cluster exactly where the poem is doing its most important work.
Sound effects work alongside the meter too. Sonnet 129 crowds stressed monosyllables together in line 4, “Savage, extreme, rude, cruel, not to trust,” so the line reads as a series of blows. The five-beat frame is still there underneath, but the words strain against it.
Iambic Pentameter in the Plays
In the plays, most of the verse is blank verse, unrhymed iambic pentameter, but Shakespeare mixes it with prose and with other forms, and the switches are often meaningful.
Nobles and lovers usually speak in verse, while comic characters, servants, and people in private or disordered moments often speak in prose. The shift can mark a change in a character. Lady Macbeth speaks commanding verse early in Macbeth, but in the sleepwalking scene of Act 5 she speaks only prose, as though the form that carried her ambition has fallen away.
Not all of Shakespeare’s verse is pentameter either. The fairies of A Midsummer Night’s Dream and the witches of Macbeth speak in shorter, chant-like lines, as in “Double, double toil and trouble.” Rhymed couplets often close a scene. And Romeo and Juliet’s first conversation, in Act 1, Scene 5, is shaped as a complete shared sonnet.
For much more on how blank verse works on stage, see our Blank Verse Guide.
How to Read It Aloud
The best way to learn to hear iambic pentameter is to read it aloud, slowly, without forcing it.
Try tapping lightly on each stressed syllable as you read. A regular line gives five comfortable taps. Where a tap feels awkward, or lands on a word that resists it, you have found a variation, and it is worth asking why it is there.
Avoid the opposite mistake of hammering every beat. Shakespeare’s verse works because the meter and the natural rhythm of speech pull slightly against each other. Read for sense first, and let the pulse sit underneath it. The meter should be felt more than heard.
Common Questions
The questions readers ask most often about iambic pentameter, answered briefly.
How Do You Identify Iambic Pentameter?
Count ten syllables, or eleven with a light ending, then read the line aloud. If about five beats fall on the even syllables, it is iambic pentameter.
How Many Syllables Are in Iambic Pentameter?
Ten in a regular line: five iambs of two syllables each. A line with a feminine ending has eleven, and elision can make a line look longer on the page than it sounds.
What Is the Difference Between Iambic Pentameter and Blank Verse?
Iambic pentameter is the meter. Blank verse is iambic pentameter that does not rhyme. Shakespeare’s sonnets are rhymed iambic pentameter; most of the verse in his plays is blank verse.
Why Did Shakespeare Write in Iambic Pentameter?
It was the standard verse line of his time, especially on the stage after Marlowe. It is long enough to hold a full thought and close enough to natural English rhythm that actors can speak it without sounding sing-song.
Did Shakespeare Always Write in Iambic Pentameter?
No. Large parts of his plays are in prose, some characters speak in shorter lines, and one sonnet, Sonnet 145, is in iambic tetrameter.
What Is an Example of Iambic Pentameter in Romeo and Juliet?
“But soft, what light through yonder window breaks?” is a perfectly regular line: but SOFT, what LIGHT, through YON, der WIN, dow BREAKS.
Related Reading
Three guides that build on what iambic pentameter does.