Punctuation that affects your band
Comma splices, fronted adverbials, semicolons, apostrophes and the however trap: the punctuation errors examiners actually mark.
- Marking criterion
- Grammatical Range and Accuracy and Coherence and Cohesion
- Where it pays off
- Writing Task 1 · Writing Task 2
Punctuation is marked as part of grammatical accuracy, and a handful of errors account for most of the damage. None of them require advanced knowledge; they require knowing where a sentence ends.
The comma splice
Two complete sentences joined by a comma is the most frequent punctuation error in IELTS writing. It is also the easiest to remove.
- Wrong: 'Online learning is convenient, it saves commuting time.'
- Fix with a full stop: 'Online learning is convenient. It saves commuting time.'
- Fix with a semicolon: 'Online learning is convenient; it saves commuting time.'
- Fix with a conjunction: 'Online learning is convenient because it saves commuting time.'
However, therefore and moreover
These are adverbs, not conjunctions, so they cannot join two clauses with a comma alone.
- Wrong: 'Costs fell, however demand did not recover.'
- Right: 'Costs fell. However, demand did not recover.'
- Right: 'Costs fell; however, demand did not recover.'
- The same applies to therefore, moreover, nevertheless, furthermore and consequently.
Commas that are required
Three positions where the comma is not optional.
- After a fronted adverbial or subordinate clause: 'In 2010, the figure peaked.' 'Although costs rose, output improved.'
- Around non-defining relative clauses and appositives: 'Tokyo, the largest city in the sample, recorded the steepest rise.'
- Between items in a list: 'housing, transport and healthcare'.
Commas that are wrong
Adding commas where none belong is as damaging as leaving them out.
- Never between a subject and its verb: 'The number of visitors, increased' is wrong.
- Never before 'that' in a defining clause: 'the policy, that reduced traffic' is wrong.
- Never around a defining relative clause.
Apostrophes and capitals
Small, visible, and quick to check in your final pass.
- Possession: 'the government's policy', 'the countries' economies' for a plural owner.
- 'Its' is possessive; 'it's' means 'it is'. Contractions are best avoided in formal writing anyway.
- Capitalise proper nouns, nationalities and languages: Japan, Japanese, English.
- Decades take no apostrophe: the 1980s, not the 1980’s.
- Contractions belong in Speaking, not in Writing. Write 'do not' and 'it is' in both tasks.
- Do not capitalise for emphasis. It reads as informal and adds nothing.
Corrected examples
Incorrect: The trend continued for a decade, however it reversed after 2015.
Correct: The trend continued for a decade; however, it reversed after 2015.
'However' cannot join clauses. Use a semicolon or a full stop before it and a comma after it.
Incorrect: In 1990 the figure stood at 12% and by 2000 it had doubled.
Correct: In 1990, the figure stood at 12%, and by 2000 it had doubled.
A fronted time phrase takes a comma, and a comma precedes 'and' when it joins two full clauses.
Incorrect: The company increased it's output, this improved profits.
Correct: The company increased its output, which improved profits.
'Its' is the possessive form, and the comma splice needs a relative clause or a full stop.
Quick checklist
- Two complete sentences never join with only a comma.
- Semicolon or full stop before however, therefore and moreover.
- Comma after a fronted phrase or a leading subordinate clause.
- No comma between subject and verb.
Apply it to a real response and check the length and structure.
Open the writing checklist