Common Grammar Mistakes That Lower Your IELTS Writing Score

Why Grammar Mistakes Matter More Than They Seem

Grammatical Range and Accuracy makes up 25 percent of your Writing score in both Task 1 and Task 2, but its effect is often larger in practice because repeated errors also distract from clarity, indirectly hurting Coherence and Cohesion as well. Fixing a small number of recurring error types can therefore raise your score more than adding new vocabulary.

Subject-Verb Agreement

A very common error is mismatching a singular subject with a plural verb or vice versa, especially in long sentences where the subject and verb are separated by other clauses, such as 'The number of students who attend university every year are increasing' (should be 'is increasing,' since 'the number' is singular). Reading your sentence aloud with only the subject and verb, ignoring the middle clause, is an effective way to catch this.

Article Errors (a, an, the)

Missing, extra, or incorrect use of articles is extremely common, particularly for candidates whose first language does not use articles the same way English does. While a single article error rarely lowers a band on its own, a pattern of frequent article errors throughout an essay signals limited grammatical range to the examiner, since correct article use is considered a basic accuracy marker.

Tense Consistency

Switching tenses without a clear reason, such as starting a sentence in the past tense and finishing it in the present, is a frequent and noticeable error. Before writing, decide which tense fits the essay overall (often present simple for opinions and general statements in Task 2), and check tense consistency specifically during your final review.

Run-On Sentences and Comma Splices

Joining two complete sentences with only a comma, rather than a conjunction or a semicolon ('The city is growing fast, it needs more housing'), is a very common structural error that limits Grammatical Range and Accuracy. This is easily fixed by either adding a conjunction ('and it needs'), starting a new sentence, or using a semicolon.

Overcomplicating Sentences to Sound Advanced

In an effort to demonstrate a wide grammatical range, many candidates write unnecessarily long, complex sentences that contain errors, which lowers the score more than a shorter, accurate sentence would. Examiners reward a genuine mix of simple, compound, and complex sentences used correctly, not complexity for its own sake.

A Practical Self-Editing Routine

In the final few minutes of each task, reread your essay specifically checking one error type at a time: first subject-verb agreement, then articles, then tense consistency, then sentence boundaries. Checking for one error type per pass is far more effective than trying to catch every kind of mistake in a single read-through.

Preposition Errors

Prepositions such as 'in,' 'on,' 'at,' and 'for' often do not translate directly between languages, leading to errors like 'depend of' instead of 'depend on,' or 'married with' instead of 'married to.' These errors are hard to self-correct through logic alone since preposition choice is largely a matter of convention rather than rule, so building a personal list of correct preposition pairings from your reading is more effective than trying to memorize a general grammar rule for them.

Why Fewer, Cleaner Sentences Beat Ambitious, Error-Filled Ones

Examiners are instructed to credit a genuine range of accurate grammatical structures, but a single ambitious sentence containing multiple errors is scored lower than two simpler, fully accurate sentences conveying the same idea. This means that during exam writing, when in doubt between a complex structure you are unsure of and a simpler one you can execute accurately, the simpler, correct option is almost always the safer choice for your overall band score.

Why Grammar Mistakes Matter More Than They Seem

Grammatical Range and Accuracy makes up 25 percent of your Writing score in both Task 1 and Task 2, but its effect is often larger in practice because repeated errors also distract from clarity, indirectly hurting Coherence and Cohesion as well. Fixing a small number of recurring error types can therefore raise your score more than adding new vocabulary.

Subject-Verb Agreement

A very common error is mismatching a singular subject with a plural verb or vice versa, especially in long sentences where the subject and verb are separated by other clauses, such as 'The number of students who attend university every year are increasing' (should be 'is increasing,' since 'the number' is singular). Reading your sentence aloud with only the subject and verb, ignoring the middle clause, is an effective way to catch this.

Article Errors (a, an, the)

Missing, extra, or incorrect use of articles is extremely common, particularly for candidates whose first language does not use articles the same way English does. While a single article error rarely lowers a band on its own, a pattern of frequent article errors throughout an essay signals limited grammatical range to the examiner, since correct article use is considered a basic accuracy marker.

Tense Consistency

Switching tenses without a clear reason, such as starting a sentence in the past tense and finishing it in the present, is a frequent and noticeable error. Before writing, decide which tense fits the essay overall (often present simple for opinions and general statements in Task 2), and check tense consistency specifically during your final review.

Run-On Sentences and Comma Splices

Joining two complete sentences with only a comma, rather than a conjunction or a semicolon ('The city is growing fast, it needs more housing'), is a very common structural error that limits Grammatical Range and Accuracy. This is easily fixed by either adding a conjunction ('and it needs'), starting a new sentence, or using a semicolon.

Overcomplicating Sentences to Sound Advanced

In an effort to demonstrate a wide grammatical range, many candidates write unnecessarily long, complex sentences that contain errors, which lowers the score more than a shorter, accurate sentence would. Examiners reward a genuine mix of simple, compound, and complex sentences used correctly, not complexity for its own sake.

A Practical Self-Editing Routine

In the final few minutes of each task, reread your essay specifically checking one error type at a time: first subject-verb agreement, then articles, then tense consistency, then sentence boundaries. Checking for one error type per pass is far more effective than trying to catch every kind of mistake in a single read-through.

Preposition Errors

Prepositions such as 'in,' 'on,' 'at,' and 'for' often do not translate directly between languages, leading to errors like 'depend of' instead of 'depend on,' or 'married with' instead of 'married to.' These errors are hard to self-correct through logic alone since preposition choice is largely a matter of convention rather than rule, so building a personal list of correct preposition pairings from your reading is more effective than trying to memorize a general grammar rule for them.

Why Fewer, Cleaner Sentences Beat Ambitious, Error-Filled Ones

Examiners are instructed to credit a genuine range of accurate grammatical structures, but a single ambitious sentence containing multiple errors is scored lower than two simpler, fully accurate sentences conveying the same idea. This means that during exam writing, when in doubt between a complex structure you are unsure of and a simpler one you can execute accurately, the simpler, correct option is almost always the safer choice for your overall band score.