I've marked thousands of IELTS essays, and here's what I see constantly: students mix formal and informal language in the same paragraph, then wonder why they're stuck at Band 6.
This isn't a small problem. It directly affects your Lexical Resource and Grammatical Range scores, which together make up 50% of your writing grade. Get this wrong, and you're capping yourself at Band 7 no matter how good your ideas are.
The truth is simpler than you think. IELTS Writing Tasks 1 and 2 demand academic register. That means formal language. But knowing the rule and actually writing it are two completely different things. Let me show you how to nail this.
Academic register is the language you'd use in a university essay, a professional report, or a formal letter. It's not fancy for fancy's sake. It's about being precise, objective, and appropriate for the context.
Think of it like dressing for an interview. You wouldn't wear gym clothes. You wouldn't wear a Halloween costume either. You'd wear business attire. That's what academic register does for your IELTS essay: it fits the occasion perfectly.
In IELTS, your examiner is looking at whether you can shift your language to match the task. Can you drop casual speech? Can you use complex sentence structures? Can you choose sophisticated vocabulary when it matters? That's what separates Band 7 from Band 8.
Let me break down the actual differences. Most students know they shouldn't use "gonna" or "wanna," but they miss the subtler stuff that pulls your IELTS formal language score down.
Here's the thing: contractions are informal. Don't use them in your IELTS essays. Ever.
Weak: "The government can't ignore climate change. It's becoming a serious problem, and we've got limited time."
Strong: "The government cannot ignore climate change. It is becoming a serious problem, and we have limited time."
That single change moves you from conversational to academic. Write out every contraction. Every. One.
Informal writing uses "you," "I," and "we" freely. IELTS academic writing avoids them or uses them strategically.
Weak: "In my opinion, you should recycle because we need to save the planet. I think this is obvious."
Strong: "Recycling is essential for environmental sustainability. The benefits of waste reduction are widely recognized by environmental scientists."
Notice how the second version removes the personal pronouns entirely and focuses on the ideas? That's academic register. You're not wrong to have opinions in IELTS; you're just supposed to present them without saying "I think."
This is where most students mess up. They use casual vocabulary when a more formal synonym exists.
Weak: "Using technology in classrooms is a good thing because kids learn faster. Lots of research shows this helps students do better."
Strong: "Integrating technology in educational environments enhances learning outcomes and academic performance. Empirical evidence demonstrates that digital tools facilitate student comprehension and retention."
Look at the vocabulary swaps: "using" becomes "integrating," "good thing" becomes "enhances," "kids" becomes "students," "lots of research" becomes "empirical evidence." These aren't random choices. They're standard academic vocabulary.
Tip: Start a vocabulary list right now. Every time you see a formal word in news articles or academic journals, write it down with a casual alternative. "Problem" becomes "issue" or "challenge." "Bad" becomes "detrimental" or "harmful." Keep this list handy while you write practice essays.
Phrasal verbs are incredibly common in English conversation. They're natural. Casual. But IELTS Task 2 and Task 1 essays need single, more formal verbs instead.
Compare these:
This single change can boost your band score noticeably. The IELTS band descriptors specifically mention that Band 8 writers use "a wide range of vocabulary fluently and flexibly." Swapping phrasal verbs for single formal verbs demonstrates exactly that in your IELTS writing test.
For IELTS Writing Task 1, you're writing a formal letter, a report, or describing data. The tone shifts slightly depending on the task, but the register stays academic.
In formal letters, you have specific conventions:
In reports or data descriptions, you're being even more formal:
Tip: For Task 1 reports, use synonyms for "shows" or "illustrates" to avoid repetition. Try: demonstrates, indicates, reveals, depicts, portrays, highlights, reflects. Write them on a sticky note next to your workspace so you grab a different one each time.
Task 2 essays are where IELTS formal language really matters. You're arguing a position, discussing advantages and disadvantages, or evaluating a claim. Examiners expect sophisticated academic language here.
The Band 7-8 range requires that you "use a wide range of structures with at least some accuracy." Formal language naturally pushes you toward more complex sentences. When you write in academic register, longer, more intricate sentence structures happen almost automatically.
Instead of writing simple sentences, combine them with subordinate clauses:
Weak: "Social media is bad. It makes people anxious. People spend too much time on it. This is a real problem."
Strong: "Excessive social media consumption contributes to elevated anxiety levels and diminished psychological well-being. Since users become increasingly dependent on these platforms for validation, the long-term psychological implications warrant serious consideration."
See what happened? The formal vocabulary forces you to write longer, more complex sentences naturally. You're hitting multiple IELTS criteria at once: Grammatical Range, Lexical Resource, and Task Response.
When you develop ideas in your body paragraphs, this same principle applies. Each idea needs to be expressed with formal precision, not casual simplification. Our band score guides show you exactly what Band 7 and Band 8 responses look like in practice.
After years of marking essays, I've noticed the same mistakes appearing over and over. Here are the top ones:
1. Using "very" instead of more precise adverbs. "Very important" sounds informal. Say "critically important" or "essential." "Very good" becomes "exceptional" or "outstanding."
2. Saying "a lot of" or "lots of." Use "a significant number of," "considerable amounts of," or "substantial quantities of." These signal that you understand formal academic writing.
3. Starting sentences with "because." I see this constantly. "Because technology is changing, education must adapt." This feels informal. Restructure: "Due to rapid technological advancement, educational institutions must evolve their approaches."
4. Using "also" repeatedly. Formal alternatives include "additionally," "furthermore," "moreover," "in addition to," or simply restructuring your sentences to avoid the connector altogether.
5. Asking rhetorical questions in your essay. "Is technology bad? Of course not!" This is conversational. Save direct address for spoken English. Instead: "The assumption that technology is inherently detrimental is demonstrably false."
Here's what actually works. Don't just read about formal language. Rewrite.
Find three sample IELTS essays online. Read them and identify every formal language feature: the vocabulary choices, the sentence structures, the way they avoid personal pronouns. Then, take an informal piece of writing (maybe something you wrote, or a casual article) and rewrite it in academic register. Change every contraction, swap out casual vocabulary, restructure sentences to be more complex.
Then, most importantly, submit your essays somewhere they'll be marked. Grade your essays to see exactly where your register is slipping. You'll get specific feedback: "This phrase is too casual here" or "Consider a more formal synonym." That immediate feedback is what makes the difference between knowing the rule and actually applying it.
Spend 30 minutes a day for two weeks doing this, and you'll notice the shift in your own writing immediately. It becomes automatic.
Not every Task 2 essay demands the same level of formality, though all require academic register.
In opinion essays where you agree or disagree, you can afford a slightly more assertive tone: "This view is fundamentally flawed" carries more weight than "I don't agree with this." But you're still using academic language.
For discussion essays that present both views, neutrality is crucial. Never say "I think Side A is better." Instead: "Proponents of Side A argue that..." and "Critics contend that..." This language is more formal and demonstrates balanced thinking.
In advantages and disadvantages essays, formality helps you compare fairly. "The primary advantage is that..." sounds more credible than "One good thing is." Browse sample IELTS essay topics to practice different essay types with the correct register.
Before you submit any IELTS essay, run this test. Read your introduction aloud. Would a university professor accept this paragraph in an academic paper? If you hesitate, it's not formal enough.
Here are quick checks:
If any of these appear in your draft, fix them. This takes 10 minutes and can move you from Band 6 to Band 7.
IELTS Writing Task 1 and Task 2 are each worth 50% of your writing score. Within each task, four criteria are assessed: Task Achievement, Coherence and Cohesion, Lexical Resource (vocabulary), and Grammatical Range and Accuracy. Your use of formal language directly impacts both Lexical Resource and Grammatical Range, making it critical to your overall result.
An IELTS essay should be at least 150 words for Task 1 and 250 words for Task 2. Formal academic register naturally supports hitting these word counts without padding, since formal language tends to be more elaborate and precise than informal speech.