IELTS Writing Task 1 Grammar Errors Checker: Band Score Guide

Grammar mistakes in IELTS Writing Task 1 aren't just annoying typos—they tank your score. Fast. The official band descriptors are crystal clear: examiners assess your "Grammatical Range and Accuracy" as one of four pillars of your writing mark. A Band 7 essay can plummet to Band 5 if grammar errors pile up. You need to know which mistakes hurt most, how to spot them before submission, and exactly how they affect your band score.

Most students catch obvious errors like "he go" instead of "he goes." The real damage comes from mistakes you don't see: incorrect prepositions, dangling modifiers, tense inconsistencies, and subject-verb agreement errors that slip past spell-checkers. This guide shows you what examiners actually penalize, with real IELTS examples and concrete fixes you can use in your next practice essay.

Why Grammar Errors Cost You Band Points in Task 1

The IELTS band descriptors for grammatical accuracy don't leave room for negotiation. At Band 7–8, examiners expect "mostly accurate" grammar with only occasional errors. At Band 6, errors are "sometimes" present but don't impede communication. At Band 5, errors are "frequent" and clarity starts to suffer.

Task 1 is harder to recover from than Task 2. You've got roughly 150–180 words and 20 minutes. One grammar mistake eats up a larger percentage of your total output. If you write 170 words and make 5 grammar errors, that's roughly 3% of your essay affected. In a task this short, density matters.

Here's what examiners actually do: they count errors and assess whether they block understanding. A subject-verb disagreement in your main message costs more than a missing article in a side clause. Tense shifts when describing a process? Red flag. Wrong preposition in a comparison? Noticeable but less damaging.

The 5 Common Grammar Mistakes That Kill Band Scores Most Often

Not all grammar errors are created equal. Some show up constantly in Band 5 and Band 6 essays. Others rarely occur but destroy clarity when they do.

1. Subject-Verb Agreement Errors

This is the most common mistake in Band 5 and Band 6 essays. You describe a trend, a process, or a group action, and the verb doesn't match the subject.

"Number" is singular, so it takes "has." Looks simple, but students rush in Task 1 and match the verb to the nearest noun instead of the actual subject.

"Each" is always singular. "Of the products" is a prepositional phrase that doesn't change the verb. This error appears in roughly 30% of Band 5 letters and report-style Task 1 responses.

2. Tense Inconsistency

Task 1 demands tense discipline. If you're describing a past event (formal letter, past data), stay in past tense. If you're writing about a process or procedure, use present simple.

You opened with present ("I am writing"), but then flipped to past ("received"). Commit to it. Your complaint and the staff's behavior happened in the past. The act of writing happens now, but that opening phrase is a formulaic opener—it doesn't lock you into present tense for the whole letter.

3. Missing or Incorrect Articles (a, an, the)

Articles seem minor, but examiners notice patterns. Using "the" when you should use "a," or dropping articles entirely, signals Band 6 or lower writing.

"Refund" is countable here (you want one refund, not all refunds in existence), so it needs the indefinite article "a." This is learnable. The real issue isn't that articles are complex—it's that students skip the edit step.

4. Preposition Errors

Prepositions don't follow strict logic in English. You have to learn them. But certain preposition errors show up constantly in Task 1.

You're satisfied "with" something, not "in" it. Band 6–7 writers make this mistake all the time. It doesn't destroy meaning, but it sounds unpolished and flags you as non-native.

5. Sentence Fragments and Run-on Sentences

A sentence fragment is a group of words that looks like a sentence but lacks a main verb or independent clause. A run-on sentence smashes two independent clauses together without proper punctuation or conjunctions.

That second sentence is a fragment. It starts with "Especially," a word that depends on the previous sentence for meaning. Combine them or restructure.

How Grammar Errors Map to IELTS Band Scores

The IELTS band scale runs from 1 to 9. Writing is scored on four criteria, each equally weighted: Task Response (or Task Achievement), Coherence & Cohesion, Lexical Resource, and Grammatical Range & Accuracy. Grammar accounts for 25% of your writing band score.

Here's what examiners see at each level:

• Band 8–9: "Errors in grammar and punctuation are rare and only as lapses rather than systematic errors." You can make maybe one or two tiny slips across your entire response.
• Band 7: "Grammar and punctuation are generally accurate, though occasional errors occur." Think 2–4 errors across 150–180 words. Mostly correct, with minor issues.
• Band 6: "Errors in grammar and punctuation occur, but they rarely impede communication." This means 5–8 errors. Readers understand you, but they notice the mistakes.
• Band 5: "Grammar and punctuation errors are frequent and sometimes obscure meaning." Expect 10+ errors. Clarity starts to suffer.

How to Spot Grammar Errors Before You Submit

You've written your Task 1 response. You've got 2–3 minutes left. What do you actually check?

Don't read your essay top to bottom. Your brain autocorrects what you meant to write, not what's actually written. Instead, scan for high-risk patterns:

1. Scan for verbs first. Underline or highlight every verb. Does each one agree with its subject? Is the tense consistent with the paragraph's context? A verb check catches 40% of grammar errors in 60 seconds.
2. Check the first verb of each sentence. If the opening verb is wrong, the whole sentence is suspect. "The data shows" vs. "The data show" (British English prefers "show" for collective nouns). Verify this immediately.
3. Read backward, sentence by sentence. This forces you to read for correctness, not meaning. You'll catch "are increase" instead of "are increasing" because you can't coast on context.
4. Mark any sentence longer than 25 words. Long sentences trap grammar errors. Break them into two sentences or verify that commas and conjunctions are used correctly.
5. Check prepositions after adjectives you used. "Satisfied with," "grateful for," "concerned about," "focused on." These pairs are fixed in English.

Common IELTS Letter Grammar Mistakes: Real Examples

Task 1 letters have their own grammar traps. Formal letter structure creates predictable problems.

Opening Phrase Mistakes

Use "to" before an infinitive, not "for." This is the standard formula.

Dangling Modifiers in Explanations

The first version implies "your company" waited three weeks. You did. Use "After" or restructure so the subject matches the modifier. For more on formal letter tone issues, check out our letter tone checker guide.

Incorrect Passive Voice

"Occur" is intransitive; it doesn't take passive voice. You can't "be occurred." This error signals Band 5–6 writing immediately.

Using an IELTS Writing Checker Smartly (And Their Limits)

Automated grammar checkers like Grammarly catch surface errors: missing commas, obvious typos, some subject-verb disagreements. They're useful, but they make mistakes too.

Grammarly might flag "The data show an increase" as incorrect because Grammarly defaults to American English (which prefers "data shows"). But British English, which IELTS uses, accepts "data show." Don't blindly accept every suggestion from an online IELTS writing checker.

Automated checkers also miss context. They can't tell whether your preposition choice is idiomatic or awkward. They'll miss a dangling modifier that changes meaning. They catch maybe 60–70% of grammar errors, which isn't enough for a Band 7 response.

What Grammar Errors Look Like at Each Band Score?

Knowing the difference between a Band 5 and Band 7 response helps you understand exactly what examiners penalize. Band 5 essays show frequent grammar errors that sometimes interfere with meaning. Band 6 essays have occasional errors that don't block comprehension. Band 7 essays are mostly accurate with only rare slips. The key difference isn't one error per se—it's the overall pattern and severity.

When you submit a practice essay to an IELTS writing evaluator or correction service, look for whether your errors fall into "frequent," "occasional," or "rare" categories. That's your real band indicator.

Build Your Grammar Accuracy Over Time

You can't overhaul your grammar in one week. But you can target the mistakes that hurt most.

Start a grammar error log. Every time you make a mistake in practice essays, write it down with the correction. After 10 practice Task 1 responses, patterns emerge. Do you consistently misuse prepositions? Do you shift tenses accidentally? Do you forget articles? Once you know your weak spots, you can create a personal checklist for exam day.

Before your real IELTS, write 3–5 full timed Task 1 responses. Time yourself for 20 minutes, then spend 2 minutes checking grammar using your personal checklist. This trains your eye to catch your own mistakes.

The goal isn't perfection. It's reducing errors to Band 7 levels: maybe 2–3 small mistakes in 170 words. That's achievable with focused practice and the right feedback from an IELTS writing correction tool.

How to Improve Your Band Score Beyond Grammar

Grammar is one piece. If you're aiming higher, you also need to nail letter openings, closings, and tone. Our guide on letter opening mistakes breaks down exactly what examiners want to see in your first sentence. Similarly, letter closing mistakes cost students points they don't expect.

For report-style Task 1, make sure your overview paragraph is strong. A weak overview paragraph will identify missing key information that tanks your Task Achievement score.

Ready to see how an IELTS writing grader evaluates your work? Use our free IELTS writing checker to get instant feedback on grammar, task response, coherence, and vocabulary across any essay you write.