Here's the thing most students don't realize: one grammar mistake won't sink your IELTS writing checker score. But make five of them? That's the difference between Band 6 and Band 7. Examiners aren't looking for perfection. They want to see you've got consistent control over your sentences. This guide shows you exactly which grammar mistakes cost you points and how to catch them before you hit submit.
Task 1 makes up 33% of your Writing band. Your grammar gets assessed under one criterion: Grammatical Range and Accuracy. At Band 7, examiners want "generally accurate" writing with only occasional errors. Band 6 gives you some room, but mistakes get noticed. Band 5 and below, and errors start affecting whether your reader even understands what you're saying.
Here's what makes Task 1 different from Task 2: you're not writing an opinion piece. You're describing data, trends, and processes. Your sentences need to be straightforward, clear, and tight. No room for ambiguity.
Here's the math: Task 1 is shorter than Task 2. One error in 150 words is 0.67% of your content. One error in 250 words is 0.4%. The error density matters more in Task 1 because every mistake stands out.
Students make the same errors over and over. Here are the five that examiners mark most heavily when you use an IELTS task 1 grammar checker.
The subject and verb need to match in number. It sounds simple, right? Yet this is the number one error I see in Task 1.
Weak: "The data shows that consumption of fruits have increased over five years."
The subject is "consumption" (singular). It needs the singular verb "has", not "have".
Better: "The data shows that consumption of fruits has increased over five years."
Watch out for prepositional phrases sneaking between the subject and verb. "The number of people in the cities" uses a singular subject (number), so you need "is". "The people in the cities" is plural, so use "are".
In Task 1, you're describing what you see in a chart or diagram. Pick past tense for historical data or present tense for general facts. Then stick with it.
Weak: "Sales increased by 30% in 2019. They reach their peak in 2020 and then declined afterwards."
You jumped from past tense to present ("reach"). This looks careless.
Better: "Sales increased by 30% in 2019. They reached their peak in 2020 and then declined afterwards."
Missing or wrong articles ("a", "an", "the") are everywhere in Task 1. The rule is simple but students forget it constantly. Use "the" with specific nouns and "a/an" with general or first-mention nouns.
Weak: "Graph shows increase in unemployment. The unemployment rate rose from 5% to 8%."
"Graph" needs an article. You're talking about the specific graph the reader is looking at.
Better: "The graph shows an increase in unemployment. The unemployment rate rose from 5% to 8%."
Preposition errors won't destroy comprehension, but examiners mark them as grammar mistakes. Students constantly mix up "to", "by", "with", "in", and "at".
Weak: "The population grew with 2 million people during the period."
"Grew with" is wrong. When talking about amounts of increase, use "by".
Better: "The population grew by 2 million people during the period."
A sentence fragment is incomplete. A run-on joins two sentences without proper punctuation. Both cost you points.
Weak: "The chart displays energy consumption. Between 2010 and 2015."
"Between 2010 and 2015" is a fragment. It's not a complete sentence on its own.
Better: "The chart displays energy consumption between 2010 and 2015."
You need to understand what examiners are looking for to know where you stand. Here's how IELTS officially scores Grammatical Range and Accuracy in Writing Task 1.
Let's say your Task 1 is 160 words and you make 3 grammar mistakes. That's roughly one error every 53 words. If all three are minor (a misplaced article, a wrong preposition), you're looking at Band 6 territory. If one is a major error (subject-verb disagreement in a key sentence), you drop to Band 5-6. Make 5+ errors and you're at Band 5.
Remember: Examiners take a holistic approach. They're not counting every single comma mistake. But patterns matter. If you consistently mess up subject-verb agreement, that hurts more than one isolated typo.
At Band 7, errors should occur "only occasionally". In a typical 150-180 word Task 1, that means 0-2 minor errors. One major error, like consistent subject-verb disagreement across multiple sentences, drops you to Band 6. The key is that your grammar mistakes don't follow a pattern. An IELTS essay checker tool will flag consistent errors more heavily than random ones.
Different Task 1 question types trip you up in different ways. Here's what to watch for.
These need you to compare and describe trends over time. Watch for tense shifts and broken comparison structures.
Weak: "In 2010, France produces 50% of the energy from renewables. By 2020, this figure has risen to 75%."
You switched from past simple to present perfect for no reason. Both timeframes are historical.
Better: "In 2010, France produced 50% of the energy from renewables. By 2020, this figure had risen to 75%."
Processes use passive voice heavily. This is where examiners really test your grammar control. Passive voice mistakes are marked harder because they're more obvious.
Weak: "The materials are extract from the ground. They are then transport to the factory."
You're missing the past participle form. It should be "extracted" and "transported".
Better: "The materials are extracted from the ground. They are then transported to the factory."
Maps require spatial prepositions and directional language. Preposition errors show up everywhere here.
Weak: "A new shopping centre is located in the west from the city centre."
Better: "A new shopping centre is located to the west of the city centre."
You've got 20 minutes for Task 1 total. Here's how to spend 2-3 minutes catching grammar mistakes before you submit.
Step 1: Find every subject and verb. Read through and underline who or what is doing the action, plus the verb. Does the verb match the subject in number? Do this first because it's the most common error.
Step 2: Check if your tenses match. Highlight all your verbs. Are they the same tense throughout? They should be, unless you're deliberately comparing two time periods.
Step 3: Verify every article. This takes time but saves points. Go through and check that every noun has "the", "a", or "an" in front of it, or is a proper noun or uncountable noun. Every single one.
Step 4: Double-check prepositions in key sentences. If you've written "increased to 50%", "decreased by 30%", or "rose from 10% to 15%", pause and verify these are correct.
Step 5: Make sure sentences are complete. Any sentence starting with "Because", "Although", or "While" needs to connect to an independent clause. Never leave it hanging by itself.
Pro tip: Don't try to check everything at once. Your brain will miss patterns if you scan too fast. Do one category at a time. Subjects and verbs first, then tenses, then articles, then prepositions. You'll catch more this way.
Let me show you three actual Task 1 sentences and exactly how examiners would mark them using IELTS writing correction principles.
Example 1: Line graph description
Weak: "The data reveals that the number of students who studies engineering have decreased significantly over the past decade."
Two errors: "studies" should be "study" (plural subject), and "have" should be "has" (number is singular). This hits the same skill twice, so you lose more points than if you made two different types of errors.
Better: "The data reveals that the number of students who study engineering has decreased significantly over the past decade."
Example 2: Bar chart description
Weak: "France showed the highest consumption, with 8.5 million tonnes. Germany was the second, with 7.2 million tonnes."
"Germany was the second" is awkward. The right phrasing is "Germany was second" or "Germany came second". This is an article and word choice error combined.
Better: "France showed the highest consumption, with 8.5 million tonnes, while Germany came second, with 7.2 million tonnes."
Example 3: Process diagram
Weak: "The coal is dig up from the earth, then it is send to power station, and finally electricity is generate."
Three errors in one sentence: "dig" should be "dug", "send" should be "sent", and "generate" should be "generated". All passive voice mistakes. This is careless and examiners will mark it as Band 4-5.
Better: "The coal is dug up from the earth, then it is sent to the power station, and finally electricity is generated."
You can't rely on spell-check or auto-correct. Microsoft Word flags some grammar errors, but it misses IELTS-specific mistakes and gives false positives. Using a dedicated IELTS writing checker gives you feedback designed for the test itself. Here's what actually works alongside any tool you use.
Read your answer out loud. Your ear catches things your eyes miss. If a sentence sounds choppy or off when you say it, something's probably wrong.
Keep a personal error checklist. Write down the five mistakes you make most often. Before you submit, check only for those five. This is way faster than checking everything and you'll catch more.
Study Band 8 Task 1 samples. Look at how high-scoring answers handle grammar. How often do they use passive voice? Do they use relative clauses? What prepositions do they choose? This trains your eye.
Time yourself on the grammar check. If you spend 4 minutes on grammar, you've lost time from writing content. Aim for 2-3 minutes. Quality over trying to be perfect.
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