The Most Common Grammar Mistakes in IELTS Writing

Grammar errors are the most visible weakness in any IELTS essay. While one or two mistakes will not destroy your score, repeated errors — especially in basic structures — signal to the examiner that you do not have the control needed for Band 7.

The good news: most candidates make the same mistakes. Fix these ten, and you will eliminate the majority of grammar errors in your writing.

This is not a comprehensive grammar textbook. It is a targeted list of the errors that IELTS examiners see most often and that have the greatest impact on your Grammatical Range and Accuracy score.

1. Subject-Verb Agreement

This is the most basic grammar rule, yet it is one of the most frequently broken in IELTS essays.

The rule: A singular subject takes a singular verb. A plural subject takes a plural verb.

Common error: "The number of students who study abroad have increased."

Correct: "The number of students who study abroad has increased."

The subject is "the number" (singular), not "students" (plural). The phrase "of students who study abroad" is a modifier — it does not change the subject.

Another common error: "One of the main reasons are the lack of funding."

Correct: "One of the main reasons is the lack of funding."

"One" is the subject, not "reasons."

Watch out for: Sentences where the subject and verb are separated by a long phrase. Identify the true subject before choosing your verb.

2. Article Usage (A, An, The)

Articles are one of the hardest aspects of English for speakers of languages that do not have them (Chinese, Japanese, Korean, Russian, Arabic, Hindi, Turkish). Unfortunately, article errors are extremely noticeable to examiners.

Key rules:

• Use "the" for specific, known things: "The government should invest in education." (We are talking about a specific government.)
• Use "a/an" for general, unspecified things: "A good education leads to better opportunities."
• Use no article for general, uncountable, or plural concepts: "Education is important." "Children need exercise."

Common errors:

"The education is important for the development of the society."

Correct: "Education is important for the development of society."

When talking about education in general, no article is needed. "The development of society" uses "the" because it is a specific development (of society).

"Government should spend more money on the public transport."

Correct: "The government should spend more money on public transport."

"The government" needs an article because we are referring to a specific government. "Public transport" is a general concept — no article needed.

3. Run-On Sentences

A run-on sentence joins two independent clauses without proper punctuation or a conjunction.

Error: "Technology has changed the way people communicate it has made the world smaller."

Three correct options:

1. Period: "Technology has changed the way people communicate. It has made the world smaller."
2. Semicolon: "Technology has changed the way people communicate; it has made the world smaller."
3. Conjunction: "Technology has changed the way people communicate, and it has made the world smaller."

Run-on sentences are a Band 5-6 error that signals a lack of sentence control.

4. Comma Splices

A comma splice joins two independent clauses with only a comma.

Error: "Many people prefer online shopping, it is more convenient."

Correct options:

1. "Many people prefer online shopping because it is more convenient."
2. "Many people prefer online shopping*;** it is more convenient."*
3. "Many people prefer online shopping*.** It is more convenient."*

A comma alone is not strong enough to join two complete sentences. You need a conjunction, a semicolon, or a period.

5. Tense Consistency

Switching tenses randomly within a paragraph is a common Band 6 error. Each paragraph should maintain a consistent tense unless there is a clear reason to shift.

Error: "The graph shows that oil production increased from 1990 to 2000. After 2000, it decreases significantly."

Correct: "The graph shows that oil production increased from 1990 to 2000. After 2000, it decreased significantly."

When tense shifts ARE appropriate:

• Moving from general present to past evidence: "Many experts argue that climate change is the biggest threat. A recent study found that..."
• Moving from past trends to future predictions: "Sales rose steadily until 2020. They are expected to continue growing."

The rule: change tenses deliberately, not accidentally.

6. Conditional Structures

Conditionals are complex structures that demonstrate grammatical range — but only if used correctly. Incorrect conditionals are among the most penalised errors.

Common errors:

"If the government will invest more in education, the economy will improve."

Correct: "If the government invested more in education, the economy would improve." (Second conditional — hypothetical)

Or: "If the government invests more in education, the economy will improve." (First conditional — real possibility)

Rule: First conditional (real): If + present, will + base verb. Second conditional (hypothetical): If + past, would + base verb. Never use "will" in the if-clause.

7. Relative Clauses

Relative clauses (using who, which, that, where, whose) are essential for Band 7+ writing. They allow you to combine ideas into complex sentences.

Error: "Students which study abroad often develop independence."

Correct: "Students who study abroad often develop independence."

"Who" = people. "Which" = things. "That" = people or things (in defining clauses).

Error: "The city where I grew up in has changed dramatically."

Correct: "The city where I grew up has changed dramatically." OR "The city that I grew up in has changed dramatically."

Do not double up — "where" already means "in which," so adding "in" is redundant.

8. Passive Construction Errors

The passive voice is useful in academic writing and Task 1, but candidates often construct it incorrectly.

Error: "The environment is destroy by pollution."

Correct: "The environment is destroyed by pollution."

Passive construction = subject + be + past participle. Make sure you use the correct past participle form.

Error: "It was believed by many people that education should be free."

Better: "Many people believe that education should be free."

While grammatically correct, the passive version is unnecessarily wordy. Use active voice unless the passive serves a clear purpose (unknown agent, emphasis on the action rather than the actor).

9. Preposition Errors

Preposition errors are extremely common and hard to eliminate because preposition use is largely idiomatic — you have to memorise which preposition goes with which word.

Common preposition mistakes in IELTS essays:

Error	Correct
"depend of"	"depend on"
"result of doing"	"result in doing" / "result from something"
"increase of 20%"	"increase of 20%" (correct!) but "increase in crime"
"lack in funding"	"lack of funding"
"invest on education"	"invest in education"
"impact to society"	"impact on society"
"contribute for"	"contribute to"
"consist in"	"consist of"

There is no shortcut for prepositions. Read widely and note which prepositions follow common IELTS topic words.

10. Sentence Fragments

A sentence fragment is an incomplete sentence — it looks like a sentence but is missing a subject, a verb, or a complete thought.

Error: "Because many people cannot afford university education."

This is a dependent clause, not a complete sentence. It needs an independent clause to complete the thought.

Correct: "Many graduates struggle with debt because they cannot afford university education without loans."

Error: "For example, countries in Southeast Asia."

This has no verb. What about countries in Southeast Asia?

Correct: "For example, countries in Southeast Asia have invested heavily in manufacturing to drive economic growth."

Priority Order: Fix These First

If you make multiple types of errors, fix them in this order:

1. Subject-verb agreement — basic but highly penalised
2. Run-on sentences and comma splices — signals weak sentence control
3. Tense consistency — easy to fix, big impact
4. Articles — takes time but worth it
5. Relative clauses — essential for demonstrating range

To understand how grammar errors affect your overall score, see IELTS writing band descriptors explained. For a complete study plan that includes grammar improvement, read how to improve from IELTS 6.0 to 7.0.

Quick Reference: Grammar Error Checklist

Before submitting your essay, scan for:

• Subject-verb agreement (especially with long modifying phrases)
• Correct article usage (the / a / no article)
• No run-on sentences or comma splices
• Consistent tenses within each paragraph
• Correct conditional structures (no "will" in if-clauses)
• Who (people) vs which (things)
• Correct passive constructions (be + past participle)
• Common preposition combinations
• No sentence fragments

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