The IELTS Writing Grammar Mistakes That Cost the Most Marks

Grammatical Range and Accuracy is a quarter of your writing score, and the descriptor is more forgiving than most candidates assume. Band 7 asks for frequent error-free sentences and good control — not perfection.

That has a practical implication: eliminating your three most common errors moves the score more than learning new structures does, because it raises the proportion of clean sentences across the whole script.

The errors below are ordered by how often they appear.

1. Articles

The most common error in IELTS writing, and the most persistent, because it rarely obscures meaning.

Two rules cover the majority of cases:

Use *the* when the reader knows which specific thing you mean — because it has been mentioned, because it is unique, or because the context identifies it.

Use no article for general statements about plural or uncountable nouns.

The trap: society, education, pollution, technology, transport, employment, crime are uncountable and take no article when used generally. This single group accounts for a large share of article errors in IELTS scripts.

2. Subject-verb agreement across a long subject

The longer the gap between subject and verb, the more likely the slip.

The fix: when checking, find the verb and trace back to its actual subject, ignoring everything in between. The number… has. The impact… is.

Also worth knowing: the number of takes a singular verb; a number of takes a plural one. A number of students have applied.

3. Tense consistency

Task 2 essays about general truths sit in the present simple. Drifting mid-paragraph is common.

Wrong: Technology changes education. Students will used tablets and it made learning easier.

Right: Technology is changing education. Students increasingly use tablets, which makes learning materials easier to update.

For Task 1, match the chart's time frame: past data takes the past simple, undated charts and processes take the present simple, projections take future forms.

The fix: decide your default tense before writing and leave it only deliberately.

4. Run-on sentences and comma splices

Two independent clauses joined by a comma is an error, and it is frequent.

The fix: a comma cannot join two complete sentences on its own. Use a conjunction, a relative pronoun, a semicolon, or a full stop.

5. Countable and uncountable nouns

Fewer/number for countable; less/amount for uncountable. This one is visible and easy to fix.

6. Conditionals

Mixing the halves is common, and conditionals are exactly the structure that demonstrates range — so getting them right pays twice.

Wrong: If the government would invest more, the problem will be solved.

Right: If the government invested more, the problem would be solved.

Would does not belong in the if clause.

7. Word form

Using the wrong member of a word family. This is scored under both Lexical Resource and Grammar.

Economic relates to the economy; economical means cheap to run. Word-family confusions like this one are worth listing individually as you meet them.

8. Prepositions after common verbs and adjectives

Small, frequent, and easy to correct once noticed.

depend on, result in, lead to, contribute to, consist of, responsible for, concerned about, aware of, an increase in, an impact on, a solution to, a reason for

Wrong: This can lead into serious problems and is a solution for congestion.

Right: This can lead to serious problems and is a solution to congestion.

9. Overreaching for complexity

An abandoned complex sentence scores worse than a clean simple one.

Overreached: Despite of the fact that although many people believes that which the government should to intervene, however it is not always effective.

Clean: Although many people believe the government should intervene, such intervention is not always effective.

Range means a mix of structures used accurately, not maximum complexity in every sentence.

How to fix your own errors

Reading this list changes little on its own. What works is finding out which of these you produce.

1. Write one full essay under timed conditions.
2. Get it marked for grammar specifically, not just overall impression.
3. Log every error with three columns: what you wrote, the correction, and the rule.
4. Count them. Almost everyone finds three or four errors making up most of the total.
5. Check only for those three in your next five essays.

Checking for everything at once does not work — attention does not stretch that far in five minutes. Checking for three specific things does, and it is what actually raises the proportion of error-free sentences.