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The Twelve Grammar Errors IELTS Examiners See Most Often
The grammar mistakes that cost the most marks in IELTS Writing are not exotic. They are the same twelve errors, essay after essay: article mistakes, subject-verb agreement slips, comma splices, tense shifts, and a short list of others that examiners could recite in their sleep. Grammatical Range and Accuracy is a quarter of your writing score, and the difference between band 6 and band 7 in that criterion is mostly the difference between making these errors frequently and making them rarely.
The good news is that a short list is a fixable list. You do not need to relearn English grammar; you need to find which three or four of these twelve you personally repeat, and remove them. Most candidates who audit their own essays discover that over half of their total errors come from just two categories.
Here are the twelve, roughly in order of how often they appear, with the fix for each.
Errors one to four: the small words that carry big penalties
1. Missing or wrong articles. The single most frequent error, especially for speakers of Uzbek, Russian, and other languages without articles. "Government should invest in education system" needs "The government" and "the education system". The working rule: a singular countable noun almost never stands alone — it needs "a", "the", a possessive, or a plural form. When you mean the general category, use the plural: "Governments should invest".
2. Subject-verb agreement across distance. Nobody writes "the government are" with the verb next door; errors appear when words intervene: "The number of students who fail these exams are increasing." The subject is "the number", so the verb is "is". Fix: when you write a verb, trace back to the head noun of the subject and ignore everything between.
3. Singular and plural confusion. "There are many advantage", "one of the most important reason". After "many", "several", "one of the", and numbers above one, the noun must be plural. Uncountable nouns cause the mirror-image error: "informations", "advices", "researches" and "knowledges" do not exist — "information", "advice", "research" and "knowledge" stay singular.
4. Preposition errors in fixed phrases. "Depend of", "discuss about", "emphasise on". Prepositions are not chosen by logic; they belong to the verb. "Depend on", "discuss" with no preposition at all, "emphasise" likewise. Learn verbs with their prepositions as single units, exactly as you learn collocations.
Errors five to eight: sentence boundaries and verb forms
5. Comma splices. Two complete sentences joined by only a comma: "Technology improves communication, it also isolates people." English requires a full stop, a semicolon, or a conjunction: "…communication, but it also…". This error matters more than it looks, because it appears in the examiner's count of error-free sentences — one splice spoils two otherwise correct sentences at once.
6. Fragments. The reverse problem: a dependent clause posing as a sentence. "Because many people cannot afford private healthcare." That "because" clause must attach to a main clause. Fragments often appear when candidates start a sentence with "Which" or "Although" and never complete the frame.
7. Unmotivated tense shifts. An essay that discusses a general truth in the present, drifts into the past mid-paragraph, and returns without reason: "People spend hours online. They lost the ability to concentrate." Task 2 essays live almost entirely in the present simple; Task 1 reports of past data live in the past simple. Pick the tense the task requires and change it only when the time reference genuinely changes.
8. Conditional confusion. Mixing frames: "If the government would invest more, the problem will disappear." Standard patterns are worth memorising cold: real future condition — "If the government invests more, the problem will shrink"; hypothetical — "If the government invested more, the problem would shrink". The "would" belongs in the result clause, not the "if" clause.
Errors nine to twelve: the structures that break under ambition
9. Broken relative clauses. "The internet, which it has changed everything" — the extra "it" duplicates the subject that "which" already replaced. Also common: "people who is", where the verb should agree with "people". Relative clauses are the cheapest route to complex-sentence marks, so broken ones are doubly expensive.
10. Word-form errors. The right idea in the wrong part of speech: "the government should economic support poor families" instead of "economically", or "this causes environment problems" instead of "environmental". When you learn a word, learn its family — economy, economic, economically, economise — and check which slot the sentence needs.
11. Faulty parallel structure. Lists whose items do not match grammatically: "Students should read widely, taking notes, and to review regularly." All three items must share a form: "read widely, take notes, and review regularly." Examiners notice parallelism because lists are exactly where careful writers show control.
12. Passive voice malformation. "This problem can be solve", "many houses were build". The passive needs be plus the past participle: "can be solved", "were built". Related: "is consist of" — "consist" is never passive; it is simply "consists of".
How do you actually eliminate your repeated errors?
Knowing the list is not the same as escaping it. Under exam pressure, your hand writes what it has practised, so the fix has to happen in practice, not in the exam room. The loop that works:
- Write a timed essay without worrying about grammar.
- Hunt your errors using the twelve categories above, and tally which categories they fall into.
- Rewrite the essay with every error corrected — writing the correct form is what retrains the habit; merely noticing the error does not.
- Before your next essay, review your top two categories for five minutes.
Leave three to four minutes at the end of every writing test for a targeted check of your known categories only. A general "check my grammar" pass finds almost nothing under time pressure; a pass that asks "did I splice any commas, and does every singular noun have an article?" finds real errors.
Remember also what the criterion rewards: range and accuracy. The goal is not to retreat into short simple sentences — an essay with no subordinate clauses cannot reach band 7 no matter how clean it is. The goal is a mix of simple and complex sentences in which the majority are error-free. The examiner's exact framing is published in the public band descriptors on the official IELTS website.
These same accuracy habits carry over to the speaking test, where grammatical control is judged by the same logic in real time — an IELTS speaking mock test will show you which of the twelve follow you into speech.
WiderAI gives you AI-scored IELTS mock tests with instant band scores and examiner-style feedback.
Start practising freeFrequently asked questions
Which grammar mistake costs the most marks in IELTS writing?
No single error carries a fixed penalty, because examiners judge overall accuracy — the proportion of error-free sentences and whether errors impede communication. In practice, article errors and comma splices are the most damaging for most candidates simply because they occur so frequently, turning otherwise correct sentences into flawed ones.
Can I get band 7 in writing with some grammar mistakes?
Yes. Band 7 does not require perfection — it requires frequent error-free sentences and good control, with remaining errors rare enough not to obstruct the reader. A handful of slips in an otherwise controlled essay is entirely compatible with band 7 and even band 8.
Should I use simple sentences to avoid grammar errors?
No. Grammatical Range and Accuracy rewards both range and accuracy, and an essay of only simple sentences caps itself regardless of how clean it is. The winning strategy is to use the complex structures you have already mastered — usually relative clauses and one or two conditional patterns — and stop experimenting with unfamiliar structures during the exam itself.
How do I find my own grammar mistakes if I cannot see them?
Re-read your essay one sentence at a time, from the last sentence to the first — reversing the order stops your brain from skimming on meaning. Checking against a fixed personal list of your known error types also works far better than a general search, and automated feedback on practice essays can build that list for you quickly.