You've got 20 minutes to write a letter. The examiner marks you on Task Response, Coherence & Cohesion, Lexical Resource, and Grammatical Range & Accuracy. But here's what catches 70% of test takers: they don't match the tone to the letter type, and it shows immediately.
Get the tone wrong, and you lose marks on Task Response before you even write a complex sentence. That's not something you can recover from. This guide teaches you exactly how to check your letter tone before you submit, so you hit Band 7 consistency instead of Band 5 confusion.
The IELTS band descriptors don't use the word "tone" or "register" outright. But they do say this: Task Response requires you to "fully" address the task and be "appropriately written."
Appropriately written means context matters. If you're writing to your local council about a pothole, you go formal. If you're writing to a friend asking to stay at their place, you go casual. Write formally to your friend and you've failed appropriateness. Write casually to the council and you've failed appropriateness. Either way, you drop from Band 7 to Band 5 or lower on Task Response alone.
The IELTS General Training Writing Task 1 tests three letter types: formal, semi-formal, and informal. Your job is to spot which one the prompt wants, then keep every sentence in that register without slipping.
Formal letters go to organizations, government bodies, or people you don't know. A complaint to an airline. A request to a university. An inquiry to a business. You don't know them, they don't know you, and the context is official.
Semi-formal letters go to people you have some relationship with but haven't actually met, or situations that feel business-like but not cold. An email to a potential landlord. A letter to a teacher you've never met. A message to a company you've used before. There's a connection, but you're keeping things professional.
Informal letters go to friends, family, or people you know well. The tone is warm, relaxed, conversational. A letter to a friend about your vacation. A message to a cousin asking for advice. A note to a colleague who's become a friend.
The prompt tells you which one you need. Your job is to spot it, then stay consistent for all 150+ words.
The prompt gives you three clear signals about who you're writing to.
Signal 1: The relationship. Are you writing to "a friend," "your manager," "your landlord," or "the manager of a hotel"? The language tells you everything. "A friend" = informal. "The manager" = formal.
Signal 2: The context. Is this personal ("explain why you can't attend their wedding") or professional ("complain about a damaged package")? Personal almost always means informal. Professional means formal or semi-formal.
Signal 3: The request itself. Are you asking for advice, explaining a situation, or making a formal complaint? Casual requests usually signal informal. Formal requests or complaints signal formal.
Here's a real IELTS example:
Prompt: "You recently bought a piece of furniture online. When it arrived, it was damaged. Write a letter to the shop manager. In your letter, explain what was wrong with the furniture, say how it has affected you, and tell them what you want them to do about it."
Signals: You're writing to "shop manager" (formal). The context is a complaint (formal). You're making a direct request for action (formal). You're formal. Full stop.
Mistake 1: Mixing formal and informal in one letter.
Weak (mixed tone): "Dear Sir or Madam, I'm writing to complain about your service, which was honestly terrible. It really sucked. I would appreciate it if you could get back to me ASAP because I'm super frustrated."
What went wrong? "Dear Sir or Madam" and "I would appreciate" are formal. But "which was honestly terrible," "It really sucked," "ASAP," and "super frustrated" are casual or conversational. The examiner sees this shift and marks you down on coherence and register control.
Strong (consistent formal): "Dear Sir or Madam, I am writing to lodge a formal complaint regarding your service. The experience fell significantly below acceptable standards. I would appreciate your prompt response to resolve this matter."
Why this works: Formal salutation, formal verb structures ("I am writing," "fell significantly below"), formal vocabulary ("lodge," "acceptable standards," "prompt response"), complete closing, and zero slang. Tone stays formal from sentence one to the end.
Mistake 2: Using contractions in formal letters.
Weak (too casual): "I've received your email and I can't say I'm happy with what you've offered. It doesn't meet my expectations."
Contractions like "I've," "can't," "I'm," and "doesn't" belong in informal letters only. Even one contraction in a formal letter flags that you're not controlling register.
Strong (formal register): "I have received your email and I cannot express my satisfaction with the offer provided. It does not meet my requirements."
Full forms ("I have," "cannot," "I am," "does not") maintain distance and professionalism. This is what Band 7 sounds like.
Mistake 3: Forgetting to be warm in informal letters.
Weak (too stiff for informal): "Dear Friend, I hope this correspondence finds you in satisfactory condition. I am writing to inform you of my recent travels to Spain. Sincerely, [Name]"
This reads like a business letter, not a note to a friend. No warmth, no personality, no conversational energy. Formal structures ("I am writing to inform you") kill the vibe.
Strong (informal and warm): "Hi Sarah, How've you been? I just got back from Spain and I have to tell you, it was amazing. The food was incredible and the people were so friendly. I can't wait to tell you all about it when we chat. Talk soon!"
Contractions, casual greeting, exclamation marks for enthusiasm, and natural flow. This is how friends actually write. The examiner recognizes authentic informal tone, and it counts toward your Task Response score.
Before you finish your letter, run through this checklist. These are the five things that signal tone problems:
Tip: Print out your letter and highlight every contraction, informal phrase, and casual word. If your formal letter has more than two highlights, you've got a register problem. Zero highlights? You're solid.
Formal Letter Example (Band 7):
"Dear Manager, I am writing to bring to your attention a serious concern regarding my recent stay at your hotel. Upon arrival, I discovered that my booking had been incorrectly processed, and the room assigned did not match the description on your website. This inconsistency caused considerable inconvenience. I would appreciate a prompt explanation and appropriate compensation for this error. I look forward to your response within five working days. Yours sincerely, [Name]"
Why this is Band 7: No contractions, formal verbs ("I am writing," "I would appreciate"), professional vocabulary ("bring to your attention," "inconsistency," "appropriate compensation"), complete closing, and clarity throughout. The examiner sees a candidate who controls formal register completely.
Informal Letter Example (Band 7):
"Hi Mia, How've you been? I've just finished my exams and I'm so relieved it's all over! I've been meaning to reach out because I wanted to ask if you're free next month. I'm thinking of visiting and it'd be amazing if we could spend some time together. Let me know what you think! Can't wait to catch up properly. Talk soon! [Name]"
Why this is Band 7: Contractions throughout, warm greeting and closing, conversational flow, clear purpose, authentic friendly tone. The examiner sees a candidate who's comfortable with informal register and uses it naturally without texting shorthand ("u" for "you" or abbreviations that hurt clarity).
Band 5 writers make these mistakes over and over. Band 7 writers catch them.
Question marks for emphasis in formal letters. "I'm sure you understand how frustrating this situation is?" This feels informal and uncertain. Band 7 removes the question mark: "I'm sure you understand how frustrating this situation is."
Overusing exclamation marks. "I'm writing to complain about your service! It was absolutely terrible! I want a full refund!" Multiple exclamation marks in formal letters read as emotional and unprofessional. Band 7 uses one, if at all: "I am writing to lodge a formal complaint regarding your service."
Accusing language with "you." "You made a mistake" or "You provided terrible service" feels personal and aggressive. Band 7 depersonalizes: "The service provided fell below acceptable standards" or "An error occurred in processing."
Formal language in informal letters. "I would like to inquire about your availability" to a friend? It kills warmth. Band 7 writes naturally: "Are you free next week?"
If you're working on letter openings and greetings, this register awareness matters just as much. The same principle applies to closings too. Check out how to nail your letter closing without breaking register.
Understanding tone is one thing. Actually building the skill is another.
Step 1: Collect three prompts. One formal, one semi-formal, one informal. Write each letter in 20 minutes, just like the test.
Step 2: Extract your opening and closing sentences. Do they match the tone? Formal should feel distant and professional. Informal should feel warm. Semi-formal sits in the middle.
Step 3: Count contractions and vocabulary choices. Create a simple tally: "Contractions: 12," "Formal phrases: 8," "Casual phrases: 2." Now ask yourself: does this mix match the letter type?
Step 4: Read the body aloud. If you stumble or feel the tone shift halfway through, you've found a register problem. Rewrite that paragraph.
Step 5: Compare against the IELTS band descriptors. The descriptors say Band 7 shows "appropriate register." That means your tone never slips. Check every paragraph independently.
Do this for three letters and you'll develop an intuition for tone that sticks with you in the exam. When you're ready, use an IELTS letter tone checker to get instant feedback on whether your register matches the task requirements.
A tone slip happens when your letter switches register mid-way, or when formal and informal language mix together. The result: the examiner questions whether you understood what kind of letter you were writing. This directly impacts your Task Response score, which is 25 percent of your Writing Task 1 mark. One register slip can drop you from Band 7 to Band 6, or Band 6 to Band 5.
The most common slip is using contractions in formal letters. Even a single "I'm" or "don't" stands out as inappropriate. Equally problematic: using overly formal phrases in informal letters, which makes the tone feel stiff and unnatural. An IELTS writing checker can flag these shifts automatically, catching what you might miss in your own work.
Write your letter, then use an IELTS writing checker to get instant feedback on tone, grammar, and band score estimate. No guesswork.
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