Punctuation Rules at a Glance

Every punctuation mark has one main job. When you are checking a sentence and you just need a reminder — does a comma go there? is it a colon or a semicolon? — this is the card to scan. One mark, one job, one example. For the full "why" behind any of them, follow the link to the lesson.

The three that cause the most red pen

• Comma vs full stop. Two complete sentences need a full stop, a semicolon, or a joining word — not just a comma. It rained. We played. (not It rained, we played.) → End Punctuation and Commas & the Oxford Comma.
• Semicolon vs colon. A semicolon joins two equal sentences; a colon introduces what follows. → Semicolons & Colons.
• Apostrophes. it's = it is; its = belonging to it — and plurals take no apostrophe (two dogs, not two dog's). → Apostrophes & Contractions.

Keep this open for a final read-through, sort the three above, and most punctuation marks look after themselves.

Two more you will meet

• … ellipsis — shows a trailing-off or a gap: I was going to say… Use it sparingly.
• - hyphen — joins words into one idea: a well-known band, twenty-one. (Different from the longer dash above.)

Read it aloud

One habit beats any rule: read your writing aloud. Where your voice naturally stops, you usually need a full stop or a comma; where it pauses hard between two complete thoughts, a semicolon or full stop fits. Your ear catches most punctuation slips faster than a rulebook can — the card above just gives you the name for what your voice already knew.

One UK/US note: British writing often puts a comma or full stop outside a closing quotation mark, American writing inside ("stop," she said in the US; "stop", she said in the UK). Pick your variety and keep it consistent.

Where next

• Punctuation — the young-learner hub — the bigger map this sits inside
• End Punctuation — full stops, question and exclamation marks
• Commas & the Oxford Comma — the comma's many jobs
• Semicolons & Colons — the in-between marks
• Apostrophes & Contractions — it's/its and possessives