Here's the thing: most students either sound like robots writing a corporate memo or like they're texting a mate. Neither gets you a 7+.
IELTS examiners don't want robotic. They don't want too casual either. They want you to read the prompt, figure out who you're writing to, and hit exactly the right tone. That's where most students stumble.
In IELTS General Training Writing Task 1, you've got roughly 20 minutes to write one letter. That letter could be formal (complaint to a company, inquiry to a university), semi-formal (to a teacher or manager you don't know well), or informal (to a friend or family member). Your tone choice directly affects your band score on Task Response and Lexical Resource. Examiners absolutely listen for it.
By the end of this guide, you'll have a working internal tone detector. You'll know exactly how to match your register to the prompt, and you'll have concrete examples you can practice with right away. When you're done, you can use a free IELTS writing checker to test your letter against the right register.
The IELTS band descriptors explicitly mention register and style. Band 8 writers "use language precisely and appropriately." Band 6 writers manage "generally appropriate register," but band 5 writers struggle with it. That's a full band difference, sometimes the difference between getting into your target university and getting rejected.
Here's what's really happening: when you misjudge tone, you're not just being rude (though you might be). You're signaling to the examiner that you don't understand how native speakers actually navigate relationships through language. That costs you points on Lexical Resource alone, because formal, semi-formal, and informal English use completely different vocabulary sets.
Think about it. You'd never say "I'm writing to lodge a formal complaint regarding the inadequate provisions" to your friend about a terrible party. And you'd never text a hotel manager "hey mate, ur rooms r dodgy lol." The words are different. The sentence structure is different. The whole energy shifts. IELTS tests whether you can make that switch on demand.
Let's define these clearly so you can spot them instantly in a prompt.
Formal letters: You're writing to someone in authority or someone you don't know at all. A company, a government department, a university admissions office, a landlord. You keep distance. You're professional. You use their title (Dear Mr. Johnson, not Dear John). Complete sentences only. No contractions. You're solving a problem or requesting something official.
Semi-formal letters: You know the person a bit, but there's still a professional barrier. Your teacher, your manager, a neighbor you've met once, a colleague. You're friendly but careful. Contractions are fine, but you're still grammatically precise. You're more direct than formal, but you explain yourself clearly and courteously.
Informal letters: You're writing to someone you know well and feel comfortable with. A friend, a close family member, someone your own age in a casual setting. You're relaxed. Contractions feel natural. Your sentences can be shorter, choppier. You sound like yourself in written form.
The prompt tells you which one to use. Read it carefully.
You won't often see the words "formal tone" in the prompt. Instead, the prompt describes the recipient or situation, and you need to decode it.
Here are real IELTS-style examples:
Notice the language: "the manager of a hotel" signals formal. "A friend who lives abroad" signals informal. "Your English teacher" is the middle ground. The prompt is your roadmap.
Let's look at real mistakes and how to fix them.
Mistake 1: Too casual in a formal letter.
Weak: "I'm writing to complain about your hotel because honestly it was pretty rubbish. The rooms were dirty, there was no hot water like ever, and the staff didn't really care. It was a waste of money for me."
Problems: "pretty rubbish" is too casual. "Like ever" is filler speech. "Didn't really care" is vague and informal. The whole thing sounds like you're venting to a friend, not addressing a business professional.
Good: "I am writing to lodge a formal complaint regarding my recent stay at your hotel. The rooms were not adequately cleaned, the hot water supply was consistently unavailable, and the staff did not respond to my requests for assistance. This experience did not meet the standard I expected for the price paid."
Improvements: "Lodge a formal complaint" is direct and professional. "Not adequately cleaned" and "consistently unavailable" are precise. "Did not respond" is stronger than "didn't care." You sound credible and measured.
Mistake 2: Too formal in an informal letter.
Weak: "I hope this correspondence finds you in good health and high spirits. I am writing to inform you of some exciting developments in my personal life. Specifically, I have recently accepted a new position of employment, which I believe you shall find noteworthy."
Problems: "This correspondence finds you in good health" is ridiculously stiff for a friend. "I am writing to inform you" belongs in a business letter, not a personal note. It sounds fake and overwritten.
Good: "Hope you're doing well! I wanted to tell you some great news. I just got a new job, and I'm really excited about it. It's everything I was hoping for."
Improvements: "Hope you're doing well" is warm but natural. Contractions ("I'm", "It's") feel conversational. Short sentences make it sound like someone they actually know.
Mistake 3: Inconsistent register (formal and informal mixed).
Weak: "Dear Sir, I am writing to request a refund for the defective product I purchased. Tbh, it was garbage and stopped working after like 2 weeks. I expect you to sort this out asap. Yours faithfully, Jane."
Problems: "Dear Sir" and "Yours faithfully" are formal. "Tbh", "garbage", "asap" are too casual. The reader doesn't know what voice they're hearing. It sounds like two different people wrote it.
Good: "Dear Sir or Madam, I am writing to request a refund for a defective product I purchased last month. The item ceased functioning after only two weeks of normal use, which falls well short of the expected product lifespan. I would appreciate your assistance in resolving this matter. Yours faithfully, Jane."
Improvements: Tone stays consistent throughout. "Dear Sir or Madam" and "Yours faithfully" match "defective", "ceased functioning", and "I would appreciate your assistance." Same register from start to finish.
Here's where students miss the point: tone isn't just about contractions and politeness phrases. It's about vocabulary choice. Each register has its own word set, and swapping them is how you signal your tone.
Look at this comparison:
| Informal | Semi-Formal | Formal |
|---|---|---|
| fix | sort out, deal with | resolve, rectify |
| mad / annoyed | frustrated, upset | dissatisfied, displeased |
| get | obtain, receive | procure, acquire |
| think about | consider | contemplate, deliberate |
| want | would like, prefer | would appreciate, request |
| ask | inquire, request | submit an inquiry, formally request |
When you choose the formal column, your whole letter sounds formal. When you slip into informal vocabulary, your formal letter breaks. Examiners hear this instantly.
Tip: Build your own vocabulary register chart. Take 15 common words (problem, happy, bad, think, need) and write three versions of each: formal, semi-formal, informal. Quiz yourself weekly. This trains your brain to switch registers automatically.
The opening and closing set the tone immediately. Examiners read the first line and know what register they're in. Use this strategically.
Formal openings:
Semi-formal openings:
Informal openings:
Formal closings:
Semi-formal closings:
Informal closings:
Your opening and closing must match the tone of your middle paragraphs. If you open "Dear Sir or Madam" but close with "Cheers mate," you've lost credibility. Stay consistent.
Formal letters are easy to spot. Informal letters feel natural if you write to friends. But semi-formal? That's where students wobble.
Semi-formal is your "professional but friendly" zone. You're polite and clear, but not cold. You use contractions sometimes. You're warmer than formal, but more careful than informal. You sound like a good colleague or a favorite teacher.
The problem: students either go too formal (stiff, awkward) or too informal (cheeky, disrespectful) in semi-formal contexts.
Here's a test. A semi-formal letter to your teacher asking for an extension:
Too formal: "I am formally requesting an extension on the aforementioned assignment due to unforeseen circumstances that have impeded my progress."
Too informal: "can i plz get extra time on the essay? I got swamped with other stuff lol"
Right: "I am writing to request an extension on the assignment due next week. I've encountered some unexpected circumstances that have affected my progress, and I believe I'll need a few extra days to produce my best work. Would it be possible to discuss this with you?"
Notice: it's polite ("I am writing to"), it's clear (no vagueness), it's got one contraction ("I've") which feels natural, and it sounds respectful but not robotic. That's semi-formal done right.
For more on getting semi-formal letters just right, check out our guide on letter politeness and tone appropriateness. It breaks down the subtle shifts that separate a 6 from a 7.
You've written your letter. How do you know if the tone is right before you submit?
Run this checklist:
This five-minute check catches most tone errors. If you want to go deeper, use a free IELTS writing checker to analyze your vocabulary choices, formality level, and overall appropriateness against the prompt requirements.
Let's look at three different prompts and how tone shifts for each one.
Example 1: Formal Complaint Letter
Prompt: "You recently bought an expensive electronic device that stopped working within weeks. Write a letter to the manufacturer requesting a refund."
This is formal because you don't know the manufacturer and you're seeking official action. Watch how every choice reinforces formality:
"Dear Sir or Madam, I am writing to request a full refund for a faulty device purchased on 15 March 2024 (Reference: PROD-789456). The item ceased functioning after only eight days of normal use, despite being brand new. Given that the device failed so soon after purchase, I believe this constitutes a manufacturing defect. I would appreciate your urgent attention to this matter and expect a resolution within 14 days. I look forward to your response. Yours faithfully, [Your name]"
Formality markers: "Dear Sir or Madam" (unknown recipient), specific reference numbers (professional), "ceased functioning" (not "broke"), "manufacturing defect" (technical language), "urgent attention" (serious tone), "Yours faithfully" (formal closing).
Example 2: Semi-Formal Request
Prompt: "Write to your university accommodation office. You're unhappy with your current room and want to request a change."
Semi-formal because you're addressing staff you don't know well:
"Dear Accommodation Team, I hope you're doing well. I'm writing to request a room change. I've been in Room 412 for two months, and unfortunately it hasn't worked out as well as I'd hoped. The room is quite noisy due to its location near the main stairwell, which makes it difficult to concentrate on my studies. I'm a quiet student and would greatly appreciate a transfer to a quieter area if possible. I'd be happy to discuss this further at your convenience. Thank you for your consideration. Best regards, [Your name]"
Semi-formal markers: "Dear Accommodation Team" (known but formal), "I hope you're doing well" (friendly but professional), "I'm writing to" (direct but polite), one contraction ("I've"), "would greatly appreciate" (polite request), "Best regards" (warm closing).
Example 3: Informal Catch-Up Letter
Prompt: "Write to an old friend you haven't seen in years. Tell them what you've been up to."
Informal because it's personal and between friends:
"Hi Sarah, It's been way too long! I hope you're doing great. So much has happened since we last caught up. I finished my degree last year and I'm now working as a graphic designer, which is honestly a dream. The job's not always easy, but I'm learning loads and the team is brilliant. On the personal side, I've moved into a new flat with two housemates who are becoming good friends. Life's pretty hectic but in a good way! I'd love to hear what you've been up to. Can we grab coffee soon? Would be amazing to see you. Talk soon, Alex"
Informal markers: "Hi Sarah" (no title), "way too long" (casual language), "which is honestly a dream" (personal voice), contractions throughout ("I've", "It's", "I'm", "that's"), "brilliant" (colloquial), short varied sentences, "Talk soon" (casual closing).
If you're working on identifying letter type and tone quickly, our resource on letter salutations and register has more prompt-to-tone decoding practice.
Take this sentence and rewrite it in formal, semi-formal, and informal versions:
"I want to know if you can help me move to a different desk."
Formal: "I would like to submit a request regarding a possible desk relocation. Would it be possible to discuss the availability of alternative workspace?"
Semi-formal: "I was wondering if there might be a chance to move to a different desk. Would you be able to help me look into this?"
Informal: "Hey, do you reckon I could move desks? Would be great if you could sort that for me."
Notice how the same idea shifts completely. Try this with five more sentences from your own practice letters. This builds your instinctive register control.
Write a practice letter and use a free IELTS writing checker to analyze your tone, vocabulary choices, and register. Get instant feedback on whether your formal, semi-formal, or informal balance matches the prompt requirements.
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