What each mark does
Commas that change the meaning
Commas around a phrase mark it as extra information: the sentence still identifies who you mean without it. No commas means the phrase is essential: it tells the reader which one. Each pair below is correct, but the two versions say different things.
How strong is each break?
Commas, semicolons, colons and full stops all mark a pause, but of different strength. Picking the right one is mostly a question of how separate the two ideas are.
Where the apostrophe goes
Write the owner first, then add the apostrophe. If the owner already ends in s because it is plural, the apostrophe goes after that s.
| Owner | Rule | Example |
|---|---|---|
| One person or thing | add ’s | the manager’s office |
| A plural ending in s | add ’ after the s | the managers’ offices |
| A plural without s | add ’s | the children’s books · women’s football |
| A name ending in s | add ’s (or ’ alone, if your style guide says so) | James’s report · James’ report |
| Two owners sharing one thing | add ’s to the last name only | Sam and Lee’s project |
| Time expressions | treat like owners | a day’s work · two weeks’ notice |
British and American punctuation
Both styles are correct. Choose the one your readers expect and use it throughout.
Punctuating bullet points
The rule depends on what each bullet is. Pick one style per list and keep it the same for every item.
Hyphens in compound adjectives
An adjective is a word that describes a noun (a long report). When two words work together to describe a noun, they form a compound adjective, and a hyphen joins them so the reader takes them as one idea. The hyphen usually appears only when the compound comes before the noun.
| Pattern | Before the noun | After the noun | Why |
|---|---|---|---|
| Adjective + noun | a long-term plan | a plan for the long term | After the noun, the words are ordinary words again. |
| Number + unit | a two-page memo | a memo of two pages | The unit stays singular before the noun: two-page, not two-pages. |
| Adjective + -ing word | a good-looking design | the design is good looking | Many style guides drop the hyphen after the verb be. |
| well + past participle | a well-written report | the report is well written | A past participle is the verb form after “has”: written, made, known. |
| -ly adverb + adjective | a highly rated supplier | the supplier is highly rated | Never hyphenate after -ly: the -ly already shows the link. |
| Three or more words | an up-to-date list | the list is up to date | Hyphenate every word in the compound before the noun. |
The hyphen can change meaning: “a small-business owner” owns a small business, while “a small business owner” is a business owner who is small. For the difference between hyphens and the two dashes, see the em dash, en dash and hyphen guide.
Numbers, dates and times
Numbers carry their own punctuation rules, and they differ between countries. Use the left column for British readers and the right for American ones; international documents often use the British forms.
Ranges such as 9 to 5 and 2025 to 26 take an en dash, the mid-length dash, not a hyphen. A colon separates hours and minutes in both styles, and the colon rules guide covers its other uses in ratios and titles.
One paragraph, every mark explained
This paragraph from a project update uses eight different marks. Each numbered mark has a note giving the rule behind it.
After two weeks of testing,¹ the team found one problem:² the client’s³ payment page loads slowly on older phones.⁴ The fix is simple;⁵ the timing is harder. Priya⁶who built the pagesays it will take three to four days. Her words were, “⁷We can ship it by the 14th.” Testing runs 15⁸18 June.
- 1,After an opening phrase (“After two weeks of testing”).
- 2:A full sentence promises something; the colon delivers it.
- 3’sPossession by one client: add ’s.
- 4.Ends a complete statement.
- 5;Joins two full sentences that contrast closely.
- 6A pair of em dashes around an aside, no spaces in American style.
- 7, “ ”A comma introduces the quote; the full stop sits inside because it belongs to the quoted sentence.
- 8An en dash for a range of dates.
Marks 5 and 6 are the ones writers reach for least. The semicolon rules for professional writers show when a semicolon reads better than a full stop, and the quotation marks guide covers note 7 in both British and American style.
Check yourself: which mark fills the gap?
Choose a mark for each sentence. The explanation appears once you pick.
Guides on punctuation rules
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