7 Grammar Mistakes That Cost You Band Scores in IELTS

Why Grammar Matters More Than You Think

Here's a reality check: Grammatical Range and Accuracy accounts for 25% of your Writing score and 25% of your Speaking score. That means grammar alone determines half a band score or more.

The frustrating part? Most students don't make exotic errors. They make the same 7 mistakes repeatedly — mistakes that signal Band 6 to examiners no matter how good their ideas are.

Let's fix them.

Mistake 1: Subject-Verb Agreement

This is the most common error in IELTS essays, and it's invisible to most writers.

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

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

The subject is "the number" (singular), not "students" (plural). The words between the subject and verb often create confusion.

Common trap phrases:

• "The number of…" → singular (has, was, is)
• "A number of…" → plural (have, were, are)
• "One of the reasons…" → singular
• "Each of the students…" → singular

Quick test: Cross out the words between the subject and verb. "The number ~~of students who study abroad~~ has increased." Now agreement is obvious.

Mistake 2: Articles (a, an, the, zero article)

Articles are a nightmare for speakers of languages that don't have them (Chinese, Japanese, Korean, Russian, Turkish, and many others). Examiners notice every missing or wrong article.

Key rules that cover 80% of cases:

• The = specific, already mentioned, or unique: "The government should invest in the education system."
• A/an = one of many, first mention: "A student needs motivation to succeed."
• No article = general plural or uncountable: "Education is important." NOT "The education is important."

Wrong: "In modern society, the technology plays important role."

Right: "In modern society, technology plays an important role."

Practice tip: Read your essay aloud. Every time you say a noun, ask: "Is it specific, general, or one of many?" This habit alone can eliminate 50% of article errors.

Mistake 3: Run-On Sentences

A run-on sentence joins two complete ideas without proper punctuation or a conjunction. It's one of the fastest ways to lose marks in Writing.

Wrong: "Many people prefer working from home it gives them more flexibility."

Right (3 ways to fix it):

1. Period: "Many people prefer working from home. It gives them more flexibility."
2. Conjunction: "Many people prefer working from home because it gives them more flexibility."
3. Semicolon: "Many people prefer working from home; it gives them more flexibility."

Examiner insight: One or two run-on sentences will drop your Grammatical Range and Accuracy score. Examiners specifically look for sentence boundary errors.

Mistake 4: Incorrect Comparatives and Superlatives

IELTS data description (Task 1) and argument essays (Task 2) both require comparisons. Getting them wrong is costly.

Wrong: "This city is more safer than that one."

Right: "This city is safer than that one."

Wrong: "China has the most highest population."

Right: "China has the highest population."

Rules:

• 1-syllable adjectives: add -er / -est (tall → taller → tallest)
• 2+ syllable adjectives: use more / most (expensive → more expensive → most expensive)
• Never combine both: ~~more safer~~, ~~most biggest~~

Common comparison structures for Task 1:

• "X was significantly higher than Y"
• "X increased at a faster rate than Y"
• "X was roughly twice as much as Y"

Mistake 5: Misusing "Which" and "That" (Relative Clauses)

Relative clauses are essential for Band 7+ because they create complex sentences — one of the criteria examiners check.

Non-defining clause (extra info — use commas + "which"):

"Social media, which has billions of users, has transformed communication."

Defining clause (essential info — no commas, use "that" or "which"):

"The policy that the government introduced has been successful."

Wrong: "The students which passed the exam were happy."

Right: "The students who passed the exam were happy." (Use "who" for people, "which/that" for things.)

Mistake 6: Tense Inconsistency

Switching tenses randomly within a paragraph is a Band 6 marker. Choose a tense and stick with it unless there's a logical reason to change.

Wrong: "The graph shows that unemployment rose in 2010. By 2015, it reaches its peak."

Right: "The graph shows that unemployment rose in 2010. By 2015, it had reached its peak."

Task 1 tense guide:

• Past data → past simple ("increased," "fell")
• Describing the visual itself → present simple ("The graph shows…", "The table illustrates…")
• Future projections → future forms ("is expected to rise," "is projected to reach")

Task 2 tense guide:

• General arguments → present simple ("Education plays a crucial role…")
• Past examples → past simple ("A study conducted in 2019 found…")
• Future predictions → will/may/might ("This trend will likely continue…")

Mistake 7: Forgetting to Use Complex Structures

Band 7 requires a mix of simple and complex sentences. If every sentence follows Subject + Verb + Object, your score caps at Band 6 regardless of accuracy.

Band 6 (all simple): "Many people use social media. It has advantages. It also has disadvantages. People should use it carefully."

Band 7+ (mixed complexity):

"While social media offers undeniable benefits such as instant communication, it also poses risks that users need to be aware of. If people are not careful about their online habits, they may find themselves spending excessive amounts of time on platforms that are designed to be addictive."

Complex structures to practice:

• Conditionals: "If governments invested more in education, inequality would decrease."
• Passive voice: "It is widely believed that…", "Steps should be taken to…"
• Concessive clauses: "Although/While…, …"
• Noun clauses: "What many people fail to realize is that…"
• Participle clauses: "Having considered both sides, I believe…"

How to Actually Fix These Mistakes

Reading about grammar won't fix your errors. You need active practice:

1. Write a short essay (250 words) and then specifically hunt for each of the 7 mistakes
2. Read your essay aloud — you'll hear errors you can't see
3. Keep an error log — write down every mistake you catch, with the correction
4. Practice one mistake per day — don't try to fix everything at once
5. Use AI feedback — tools like hiseven give you sentence-level grammar analysis that highlights exactly these errors

Quick Summary

• Subject-verb agreement: Find the real subject — ignore words in between
• Articles: Specific = the, general plural/uncountable = no article, one of many = a/an
• Run-on sentences: Every complete idea needs proper punctuation or a conjunction
• Comparatives: Never combine "more" with "-er" — pick one
• Relative clauses: Who for people, which/that for things, commas for extra info
• Tense consistency: Pick a tense per paragraph and stick to it
• Complex structures: Mix simple and complex sentences — Band 7 requires both