Grammar errors in Task 1 don't just cost you a few points. They tank your Grammatical Range & Accuracy score—which is worth 25% of your total writing mark. Here's what surprises most students: you can nail the description of a chart or diagram, but one grammar mistake repeated across your essay drops you from Band 7 to Band 6. That's the difference between getting accepted and rejected at most universities.
This guide shows you exactly which grammar mistakes hurt your score, how to spot them using an IELTS writing checker, and what separates Band 8 writers from Band 5 writers.
The IELTS band descriptors for Grammatical Range & Accuracy measure two things: how varied your grammar is, and how accurately you use it. You don't need flawless grammar to hit Band 7 or 8, but you need consistent accuracy across your entire essay.
Here's what each band expects:
The key word: "occasional." Band 7 allows errors. Band 6 expects them. The real difference is control. Band 7 writers mess up only when they push themselves. Band 6 writers make mistakes even with basic structures.
Tip: Don't chase perfection. Chase consistency. Write sentences you're confident about, and save the fancy structures for when you've actually practiced them.
These aren't subtle errors hiding in obscure grammar rules. These are the mistakes that appear over and over across thousands of Task 1 essays. Fix these five, and you'll jump your score immediately.
This happens when you stick extra information between the subject and verb, and then forget what your actual subject is.
Weak: "The number of people who visits the museum have increased."
Good: "The number of people who visit the museum has increased."
"The number" is your subject (singular), not "people." The verb agrees with the real subject. Cross out the middle bits and read just the subject and verb together. "The number...has." That's the pattern.
Task 1 descriptions should stick to one tense. If the data is current, use present. If it's historical, use past. But most students jump between tenses within the same paragraph.
Weak: "In 2010, the graph shows that unemployment rises significantly and reached a peak in 2012."
Good: "In 2010, the graph shows that unemployment rose significantly and reached a peak in 2012."
Pick your main tense (usually simple past for historical data) and lock in. "Shows" works because you're describing what the graph depicts right now. But the data itself moves in past tense.
Articles (a, an, the) trip up non-native speakers constantly in Task 1, especially when describing data.
Weak: "A graph shows the increase of sales during a period between 2015 and 2020."
Good: "The graph shows an increase in sales during the period between 2015 and 2020."
Use "the" for specific things (the graph you're describing, the data, the trend). Use "a/an" for general things you mention for the first time. If it's specific and in front of you, use "the."
Wrong prepositions don't break sentences, but they make them sound awkward and drag down your score.
Weak: "There was a significant increase on the number of users at the social media platform."
Good: "There was a significant increase in the number of users on the social media platform."
The most common Task 1 preposition mistakes: "increase of" (should be "increase in"), "decrease at" (should be "decrease in"), "at 50%" (should be "to 50%" or "at 50 percent").
You connect two complete thoughts with just a comma, and suddenly your reader gets lost.
Weak: "Sales increased dramatically, the company decided to expand its operations."
Good: "Sales increased dramatically, so the company decided to expand its operations."
Or: "Sales increased dramatically. The company decided to expand its operations."
Or: "Because sales increased dramatically, the company decided to expand its operations."
You need a conjunction (and, but, so, because, although), a semicolon, or a period. A comma alone won't cut it.
An IELTS essay checker helps, but it's not your teacher. It catches surface errors but misses nuance. If a tool suggests something, understand why before you accept it blindly.
When you check IELTS Task 1 grammar online, follow this approach:
Tip: The best IELTS writing checkers explain errors, not just mark them red. You're building skill here, not fixing one essay.
Band 7 and 8 writers don't just avoid mistakes. They show range. Examiners want to see you handling simple, compound, and complex sentences with confidence.
Here's what actually impresses:
Good: "Although the overall trend shows growth, the period from 2015 to 2017 witnessed a temporary decline."
This proves you can handle dependent clauses. Don't overload your essay with them, but weave them in naturally to show control.
Good: "The data was collected from five major cities across the region."
Passive voice feels natural when describing data sources. Use it occasionally for variety—one or two passive sentences per essay is the sweet spot. Don't go overboard.
Good: "If the current trend continues, we can expect further growth in coming years."
This shows you can speculate and handle hypothetical grammar. That's Band 7 material.
Some grammar errors show up more in certain Task 1 formats. Know your weak spots.
Students mess up comparative language. You write "The red line is higher than the blue line," then shift to "The blue line increases faster." That's inconsistent tense, and it tanks your score.
Solution: Describe where things ended up (past tense) and describe the movements themselves (increases, decreases) with consistent tense. Pick one approach and commit to it the whole way through.
Subject-verb disagreement with collective nouns kills your score here. "The data shows" (correct), not "the data show." Stick with one approach for collective nouns and keep it consistent.
Run-on sentences happen because you're listing lots of percentages. "France accounted for 35%, Germany represented 28%, and the UK comprised 22%." That works. But if you drop the structure and proper punctuation, it becomes a mess. Keep your lists grammatically parallel.
Students mix imperatives with description. Don't write "First, add the flour." Write "First, the flour is added" or "In the first step, flour is added." Process diagrams need passive voice or third-person description, not commands.
You can't catch every mistake while writing. You need a system. Here's one that works.
First pass: Read for meaning. Does your essay make sense? Did you lose the thread anywhere? Fix the big stuff first.
Second pass: Read out loud. Seriously. Your ear catches what your eyes miss. If it sounds wrong, it probably is.
Third pass: Check one grammar rule at a time. Don't try to fix everything at once. Scan for subject-verb agreement first. Then tense consistency. Then articles. Then prepositions. Focused checking catches more than scanning straight through.
Fourth pass: Hunt for your personal mistakes. You have patterns. Maybe prepositions trip you up. Maybe you always write comma splices. Check only for your mistakes on the final pass.
Tip: Keep a personal error log. Every time you mess up grammar on practice essays, write it down. Before your exam, review your log. You'll catch yourself making the same mistakes during the real test.
Tools like Grammarly help, but they're trained on general English, not IELTS Task 1. They might flag "the data shows" as wrong (it's not), or they'll miss article errors in data descriptions because those constructions don't show up in regular writing.
An IELTS-specific grammar correction tool understands Task 1's unique conventions: describing trends, comparing datasets, handling percentages and figures. It knows that "there are" constructions appear constantly, that passive voice is expected, and that certain prepositions are standard in academic data writing.
Use general tools as a starting point, not your final word. When one flags something, ask yourself: "Is this actually wrong in IELTS Task 1 context?" Sometimes the answer is no.
Reading about grammar helps. Actually practicing it builds the skill.
Find a Task 1 essay you've written. Pick three sentences that use complex grammar. Rewrite each sentence three different ways without changing the meaning. This forces your brain to understand the structure, not just memorize the sentence.
Example: "The graph shows that sales increased by 50% between 2010 and 2015."
Rewrite 1: "Sales increased by 50% between 2010 and 2015, as shown in the graph."
Rewrite 2: "In the period from 2010 to 2015, sales rose by 50%, which is illustrated in the graph."
Rewrite 3: "Between 2010 and 2015, there was a 50% increase in sales according to the graph."
All three are correct. They just use different structures. By forcing yourself to find alternatives, you build flexibility and deeper understanding. When you use a free IELTS writing correction tool later, you'll spot errors faster because you understand the why behind the grammar.
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