Punctuation
Dashes and hyphens
Hyphens build words; dashes separate ideas.
Why this happens
Hyphens join compound modifiers (well-known author); en dashes show ranges (pages 4–6); em dashes mark breaks or emphasis — unlike commas or parentheses. Writers hyphenate after -ly adverbs wrongly, use hyphens where an em dash belongs, or omit hyphens in compounds that change meaning (small business owner vs small-business owner). One missing hyphen can change what you are describing entirely.
See it in a sentence
IncorrectThe well known researcher presented first.
CorrectThe well-known researcher presented first.
Teaching note: Compound adjective before a noun takes hyphens: well-known researcher.
IncorrectThree cities London, Paris, and Rome were compared.
CorrectThree cities — London, Paris, and Rome — were compared.
Teaching note: Em dashes set off an interrupting list more emphatically than commas.
IncorrectSubmit the form by 5:00-6:00 p.m.
CorrectSubmit the form by 5:00–6:00 p.m.
Teaching note: Time ranges use an en dash, not a hyphen.
More examples
A newly formed committee — no hyphen after -ly adverbs (newly formed).
Do not hyphenate after most -ly adverbs.
Em dash vs colon: One result stood out — accuracy improved.
Dash adds drama; colon expects formal elaboration.
Re-enter vs reenter — spelling varies; exams may accept one dictionary form.
Follow one consistent dictionary.
Hyphenate compound numbers twenty-one through ninety-nine when spelled out.
Twenty-one students, not twenty one students.
Quick check
We need a last minute revision before the ten page report is due.
Show the fix
We need a last-minute revision before the ten-page report is due. Hyphenate compound modifiers before nouns: last-minute, ten-page.
Practice this topic in Wrytesmart
Open the grammar workspace to complete interactive exercises for dashes and hyphens. You will spot errors, fill blanks, and transform sentences — always with teaching notes that explain the principle, not just the correction.
Master dashes and hyphens in context
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