Here's what I see constantly: students write complaint letters like they're texting a friend. Casual. Rushed. Vague about what actually went wrong. Then they're confused why they're stuck at Band 5 or 6.
The reality? Complaint letters in IELTS Task 1 have specific structural and linguistic demands. Examiners aren't looking for emotional venting. They're looking for clarity, formality, and evidence that you can organize a complaint professionally—even when you're upset. You need to sound like someone who gets results, not someone who's just angry.
This guide walks you through exactly what examiners check for, why most complaint letters fail, and how to build one that lands you Band 7 or higher. If you're working through multiple IELTS writing tasks, using an IELTS writing checker alongside this guide will show you exactly where your letter stands.
You've got roughly 20 minutes and a 150-word minimum. That's not much time. With a complaint letter, you're not just describing a problem—you're persuading someone to fix it. That requires a tone that's firm but not aggressive, clear but not robotic. It's a balancing act most students miss.
Most students make one of three mistakes:
Any one of these will cap your score at Band 6, regardless of how good your grammar is.
Your complaint letter is marked against four criteria, and each one matters equally for your final band score.
Task Response (25%): Did you write a letter? Did you include all the information from the prompt? Did you make a clear request? Band 7 requires you to "address all parts of the task clearly," use "appropriate register" (formal tone), and "organize information logically." Miss any of these and you're capped at Band 6.
Coherence and Cohesion (25%): Does your letter flow? Are your ideas connected, or do they jump around? Band 7 requires "clear progression" and "appropriate use of cohesive devices"—that's linking words, pronouns, and proper reference. If a reader can't follow your logic, you lose points here.
Lexical Resource (25%): Is your vocabulary appropriate and varied? Band 7 requires "accurate spelling and punctuation," "appropriate word choice," and vocabulary that's "less common." You're not looking for fancy words; you're looking for precise ones. "The service was inadequate" beats "really bad" every time.
Grammatical Range and Accuracy (25%): Can you use complex sentences accurately? Band 7 requires "variety of complex structures" and "minimal errors that rarely impede communication." Mix simple and complex sentences. Show range.
Notice something? It's not about sounding angry or eloquent. It's about being clear, organized, formal, and grammatically solid.
A Band 7 complaint letter follows a predictable shape. You don't need to be creative here. You need to be effective.
Paragraph 1: Opening and Purpose (2-3 sentences)
State what you're writing about. Be specific. Name the product, service, date, or booking reference if the prompt gives it. "I am writing to lodge a formal complaint regarding..." is your opening. Not creative, but it works.
Paragraph 2: The Problem (3-4 sentences)
Describe what went wrong. Use concrete details: dates, prices, what happened. This is where most students fail. They write "poor quality" instead of "the lens was cracked when I opened the box." One is vague. One is evidence.
Paragraph 3: The Impact (2-3 sentences)
Explain how this affected you. "I rely on this phone for my professional communications, so the damaged device disrupted my work schedule." This justifies your request and adds weight to your complaint.
Paragraph 4: The Request (1-2 sentences)
Say exactly what you want: a refund, replacement, repair, or apology. Be direct. "I request a full refund of £240 within seven business days" is not aggressive—it's professional.
Paragraph 5: Closing (1-2 sentences)
Say you expect a response by a certain date. Remain professional. "I look forward to your prompt response" or "I await your confirmation." That's it.
Four or five short paragraphs. No rambling. No repetition.
Here's a real IELTS-style prompt: You bought a phone online three weeks ago. It arrived damaged. Write a letter to the retailer.
Weak (Band 5): "I bought a phone from your shop three weeks ago and it came broken. I'm really upset because I needed it for work. The screen was smashed and it doesn't turn on. This is not acceptable! Please send me a new one as soon as possible. I want this solved quickly."
What's wrong? The tone is informal ("I'm really upset," exclamation marks). The request is vague ("as soon as possible" instead of a specific timeframe). Cohesion is weak (short, choppy sentences with no linking words). Vocabulary is basic ("really," "not acceptable," "quickly"). An examiner reads this and thinks Band 5 immediately.
Strong (Band 7): "I am writing to lodge a formal complaint regarding a damaged mobile phone I purchased from your online store on August 10th, 2024 (Order Reference: #12345). Upon delivery three days later, I discovered that the screen was severely cracked and the device would not power on, rendering it completely unusable. As I rely on this phone for my professional communications, this failure has caused significant disruption to my work schedule. I request that you provide either a full replacement device or a refund within seven business days. I look forward to your prompt response."
What makes this work? Formal register from the first sentence. Specific details (date, order number, exactly what was wrong). Clear consequence ("caused significant disruption to my work schedule"). An explicit, reasonable request (replacement or refund, specific timeframe—seven business days, not "soon"). Linking words that make it flow ("Upon delivery," "As I rely," "I request that"). Advanced vocabulary ("lodge," "severely," "rendering," "disruption," "prompt"). Mixed sentence structures—short and long, simple and complex.
The second version isn't flawless Band 8, but it's clearly Band 7. That's your target.
Stop trying to sound creative. Use these templates instead. They work because examiners expect them, and they naturally create the formal register that Band 7 requires.
Opening:
Describing the problem:
"On [date], I [action]. However, [problem]. As a result, [consequence]." This structure is rock solid because it's chronological and clear.
Requesting action:
"I request that you [specific action] by [date]." Never say "please fix it" or "I hope you'll help." Say "I request a refund" or "I request that you replace the item." The difference is professionalism.
Closing:
"I look forward to your prompt response" or "I await your confirmation." Both are formal without being cold.
Pro tip: Use complex sentences with subordinate clauses. Band 7 requires "variety of complex structures." Write "Although I was satisfied with the initial purchase, the delivery service failed to meet basic standards" instead of "I liked the purchase. The delivery was bad." Same idea, but the first version shows grammatical range and makes you sound more sophisticated.
Let's talk about what actually tanks your score when writing a formal complaint evaluation.
Mistake 1: Missing the prompt requirements. If the task asks you to explain the problem and request compensation, you must do both. Skipping either one automatically lowers your Task Response score. Read the prompt three times before you start writing. Seriously—three times.
Mistake 2: Using too many linking words awkwardly. Students think Band 7 means forcing "furthermore," "moreover," and "in conclusion" into every paragraph. Wrong. Use linking words where they belong: "However," "As a result," "In addition to this." If you force them, you sound stilted and robotic. Worse, the examiner notices.
Mistake 3: Being too emotional or too robotic. You're not texting your friend ("OMG so angry lol"), and you're not writing a legal document. Formal doesn't mean cold. "I am disappointed by this service" is appropriate. "I am extremely displeased by the suboptimal nature of your establishment's service" is overdone. Find the middle ground.
Mistake 4: Forgetting to include a specific date or reference number. If the prompt mentions a booking date, restaurant name, or product code, use it. This shows attention to detail and makes your complaint credible. It also fills your letter with concrete details that push you toward Band 7.
Mistake 5: Being vague about consequences. Don't just say the problem was bad. Say why it mattered to you. "The delayed delivery meant I missed my daughter's birthday and had to purchase a replacement gift at short notice" carries far more weight than "The delivery was late." Consequences justify your complaint.
You've written your letter. You have 3 minutes left. What do you actually check?
Read it aloud (silently). Does it sound like formal English, not a chat? If you find yourself reading contractions, passive voice, or casual phrases, fix them. Your ear catches what your eyes miss.
Count your paragraphs. Do you have an opening, problem, impact, request, and closing? Missing any? You need all five sections.
Highlight every action verb. "I request," "I am writing," "I discovered." Are these strong and formal, or weak ("I hope you will," "maybe you could")? Weak verbs kill your band score.
Check for vague words. Circle any instance of "bad," "good," "wrong," "nice," "really," "very," or "quite." Replace them immediately. "The food was bad" becomes "The meal was overcooked and cold." "Really poor service" becomes "inadequate service."
Verify your request is crystal clear. Can someone read your letter and know exactly what action you want? If not, rewrite that paragraph. Ambiguity costs you points.
Pro tip: Write the date, names, and reference numbers first. Then write the complaint. This prevents you from forgetting details halfway through and keeps your letter anchored in specifics instead of vague complaints.
Here's a complete example that demonstrates how to write complaint letter for IELTS with all Band 7 elements. The prompt is: You stayed at a hotel for two nights last month. The room was dirty, the staff was rude, and breakfast wasn't available as advertised. Write a complaint letter.
Dear Manager,
I am writing to lodge a formal complaint regarding my recent stay at your hotel from September 15-17, 2024. Unfortunately, my experience fell significantly short of the standard I expected from an establishment with your reputation.
Upon arrival, I was assigned to Room 412. The room was in an unacceptable condition; dust covered the bedside tables, the carpet appeared stained, and the bathroom had not been properly cleaned. Additionally, when I requested assistance from the front desk staff, I was met with indifference and dismissive replies. Most disappointingly, the full breakfast advertised on your website was not available on either morning of my stay. Instead, guests were offered only tea and toast.
These failures undermined my ability to relax and caused me considerable frustration, particularly as I had specifically chosen your hotel based on its positive reviews and claimed amenities.
I request that you provide a full refund of my accommodation costs (GBP £240) within 10 business days. I also expect an explanation regarding these service failures and confirmation of the measures you will implement to prevent similar issues.
I look forward to your response.
Yours sincerely,
[Name]
Why does this work? It hits all four band descriptors. Task Response: addresses every point in the prompt without missing a single element. Coherence and Cohesion: ideas flow logically with linking words ("Upon arrival," "Additionally," "Most disappointingly") that feel natural, not forced. Lexical Resource: vocabulary is precise ("lodge," "unacceptable," "indifference," "undermined") without being pretentious. Grammar and Range: varied sentence structures—short statements mixed with complex constructions using subordinate clauses.
Formal tone isn't about sounding robotic. It's about sounding professional and respectful, even when you're upset. When you're checking your letter tone, ask yourself: would a business manager send this letter?
Casual language gets cut immediately. Contractions (I'm, don't, won't), exclamation marks, slang, and emotional outbursts all scream "Band 5" to an examiner. But you also don't want to sound like a robot. The sweet spot is professional but human. "I am disappointed by this situation" beats both "I'm really upset!" and "The aforementioned situation has engendered considerable disappointment."
One more thing: if you're working on the actual structure and format, this guide on letter format mistakes covers the salutation, body, and closing in detail. Don't skip those basics—they're part of Task Response and evaluated alongside content.
Writing a complaint letter under exam conditions is stressful. You're thinking about grammar, tone, structure, and vocabulary all at once. That's why using an IELTS writing checker before your exam is smart—it gives you instant feedback on whether your letter actually hits Band 7, and it shows you exactly where to improve. A proper IELTS essay checker or task 1 formal complaint evaluation tool will assess all four criteria: Task Response, Coherence and Cohesion, Lexical Resource, and Grammatical Range and Accuracy.
The patterns we've covered work. The templates don't fail. But you need to practice applying them under time pressure. Write a complaint letter, check it, revise it, check it again. Do this five times, and complaint letters stop being your weakness. They become your strength.
Get instant band score feedback and line-by-line analysis from our IELTS writing checker. See exactly what's holding you back from Band 7.
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