Let's cut to it: grammar mistakes in Task 1 are stealing points you shouldn't lose. You can nail your ideas and organize everything perfectly, but one recurring grammar error will tank your Grammatical Range & Accuracy score. The band descriptors don't forgive this.
Here's what separates the bands. A Band 5 writer makes frequent errors that distract the reader from your actual argument. A Band 8 writer? They still slip up occasionally, but the mistakes appear only in complex sentences they're deliberately attempting. That's the difference you're working toward, and it's completely achievable.
This guide shows you exactly which grammar errors kill your band score, how to catch them before submitting, and how to use an IELTS writing checker strategically to spot the ones you keep missing.
The IELTS band descriptors split your writing score into four equal categories. Grammatical Range & Accuracy is one of them, which means grammar alone represents roughly 25% of your final mark. Miss this pillar, and you're stuck at Band 6 no matter how strong your Task Response is.
Band 5 says "frequent errors in grammar and spelling that cause difficulty for the reader." Band 8 says "uses a wide range of structures with high accuracy; minor errors are rare and usually only appear in very complex sentences." That gap is real, and most students think they'll close it by just writing more. They won't.
You need to know what to look for. You need to see the pattern in your own mistakes before you can fix it.
This trips up more students than anything else, especially when words pile up between the subject and verb, or when you're dealing with collective nouns.
Band 5: "The number of people who uses public transport have increased significantly over the past decade."
Band 7: "The number of people who use public transport has increased significantly over the past decade."
"Number" is singular, so the verb needs to be "has," not "have." Also, "people" is the object of the preposition inside the phrase, not your subject. So "who use" is right (plural). Most students flip both parts around.
In Task 1 letters, you shift between past, present, and future naturally. The problem is when you do it by accident, without a real reason.
Band 5: "I am writing to complain about the faulty product I purchased last week. The screen was broken, and the customer service team refused to help me. I am expecting a full refund."
Band 7: "I am writing to complain about the faulty product I purchased last week. The screen was broken, and the customer service team refused to help me. I expect a full refund."
Use "expect" (simple present) because you're stating what you want right now, not some distant future moment. The Band 5 version flips tenses without any grammatical reason.
Band 7+ writers use passive voice strategically. Band 5 writers use it and then break it.
Band 5: "The report is been sent to you yesterday."
Band 8: "The report was sent to you yesterday."
"Is been" doesn't exist in English. Pick one: "is being sent" (present continuous passive) or "was sent" (simple past passive). Don't mix them.
This looks like an advanced mistake, but examiners spot it constantly in Band 5 and 6 writing. It signals careless thinking.
Band 5: "Walking into the office, the temperature was uncomfortable."
Band 7: "When I walked into the office, I found the temperature uncomfortable."
The Band 5 version makes it sound like the temperature was doing the walking. The modifier "walking" must logically connect to whoever's actually walking. Rewrite to make that crystal clear.
This is a hybrid spelling and grammar mistake, and it wrecks your score because examiners read it as sloppy.
Band 5: "The company is losing its reputation due to it's poor service."
Band 8: "The company is losing its reputation due to its poor service."
The rule is simple: "it's" only works when you can replace it with "it is" or "it has." "Its" is possessive. Write out both versions in your head and you'll catch this every time.
An IELTS writing correction tool isn't supposed to write for you. It's supposed to catch patterns you're missing and teach you the rule. This matters.
When you run your Task 1 letter through a checker, don't just accept the correction and move on. Read the explanation. Ask yourself: "Why was this wrong?" Write the rule down. If the same error pops up in your next essay, that's a personal weak spot. Add it to your study list.
Real talk: Use a grammar checker on 5 to 7 practice essays total before test day. Don't lean on it for every sentence, or you'll never build your own proofreading radar. Aim to be 80% accurate on your own, then use the tool to catch that final 20%.
The main trap: tense chaos. You're jumping between the past (when you received the broken product), present (how you feel right now), and future (what you want to happen). Lock it down: past for what happened, present for your feelings, future only for your request.
Band 5: "I purchased the laptop three weeks ago. It will malfunction immediately. I am demanding a replacement."
Band 7: "I purchased the laptop three weeks ago. It malfunctioned immediately. I am demanding a replacement."
Common problem: tangled conditionals. Use consistent structures: "If you could provide X, I would appreciate it" works. "If you could provide X, I will appreciate it" doesn't. Getting conditionals right is Band 7+ territory.
Watch your gratitude phrasing. "I am grateful for your help" works fine. "I thank you for your help" also works. But "I am thanking you" (present continuous) sounds stiff and costs you sophistication points. Pick the natural version and stick with it.
Understanding what examiners actually see at each level matters. It tells you what you're aiming for.
Band 5: Errors are everywhere. You're mostly using simple sentences. When you try something complex, it falls apart grammatically. Your writing has consistent grammar mistakes and spelling errors that make reading difficult.
Band 6: Some errors, but they don't derail the reader. You're using more complex structures and getting them right about 70 to 80% of the time. These IELTS letter writing grammar mistakes are less frequent and don't obscure meaning.
Band 7: Mostly accurate. You use a range of tenses and sentence structures. When errors show up, they're in ambitious sentences, which is actually okay because it shows you're taking risks with advanced grammar. Grammar errors band score improvements are visible here.
Band 8: High accuracy across everything. Errors are rare and minor (a misplaced comma, not a tense mess). You vary sentence length on purpose, not by accident.
The Band 5 to 6 jump is about accuracy. Band 6 to 7 is about range and consistency. Band 7 to 8 is about controlling complexity without sacrificing correctness.
Print your practice essay. Read it out loud. This sounds boring, but it works because your ear catches grammar mistakes your eyes skip over. It's especially powerful for spotting subject-verb agreement problems and tense shifts.
Build a personal error checklist based on what you've found in previous practice essays. Before you submit, scan only for those specific errors. Always mix up "its/it's"? Scan for that first. Lose tense control in middle paragraphs? Read that section three times specifically for tense consistency.
This targeted approach beats trying to proofread everything at once. You can't hold fifteen grammar rules in your head simultaneously.
Pro tip: After writing your Task 1 letter, wait at least 10 minutes before reading it again. The distance helps you stop reading what you meant and start reading what you actually wrote.
Write one Task 1 letter per week. Check it with a grammar errors checker. Write down every error. Find the rule and jot it down. Review that list before your next letter. After 8 to 10 weeks, you'll start catching your own mistakes without the tool.
Don't write five essays in a week expecting to improve. You won't retain anything. One essay per week, done carefully, beats five essays done carelessly.
Keep a simple spreadsheet: date, topic, errors found, error category. After 10 essays, you'll see your personal pattern. Maybe you always mess up articles. Maybe it's prepositions. Maybe tense control breaks down in your middle paragraph. Once you spot the pattern, attack it directly.
For additional guidance on strengthening other Task 1 weak spots, check out our guide on fixing weak overview paragraphs. A strong overview actually sets you up to use grammar more confidently in the body paragraphs. You can also explore our IELTS band calculator to track your progress as your grammar improves.
Use a dedicated IELTS writing checker tool that flags specific grammar mistakes and explains why they matter for your band score. The best approach combines an online checker with manual proofreading: run your essay through the tool, learn the rules behind each correction, then practice catching those errors yourself on new essays.
If you're working on improving your overall Task 1 accuracy, our guide on catching data accuracy mistakes pairs well with grammar work. Grammar plus accuracy equals a solid climb up the band scale. You can also review IELTS writing task 1 grammar error patterns across multiple topics using our IELTS essay topics collection.
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