Prep sites love a clean number: study for X hours and gain a band. The research behind those numbers is messier. Below is what the actual sources say, with their conditions kept and clearly marked as averages or general guidance rather than a promise, plus a practical way to work out where you personally stand.
Why there's no single answer to "how many hours"
IELTS.org says there is no simple answer to how long it takes to reach a band score. An IELTS handbook figure of up to 200 hours per band for individuals was used until 2002, but Cambridge research later concluded that a one-band-per-200-hours formula cannot be supported - specifically, a 2004 article by Tony Green of Cambridge ESOL's Research and Validation Group (Research Notes 16, on IELTS Writing score gains) concluded that the available evidence does not support a formula of one band per 200 hours of intensive study. Even so, if you search for how long it takes to raise an IELTS band you will often see a "200 hours per band" figure repeated online, sometimes presented as if it were current IELTS guidance.
Some partner-run sites, such as IDP IELTS Vietnam, publish rough month-based estimates, which are general guidance rather than research (see below). That doesn't make estimates useless; it means no hours figure should be treated as a countdown or a promise for any one person.
Everything below is presented on that basis: what the sources named actually report, not a promise about how long it will take you. IELTS.org lists many factors that affect how quickly you improve, including your current level, the time you have to prepare each day or week, your first language, the help you receive, your motivation and how anxious you feel about the test.
The figures you'll see quoted, and where they come from
| Figure | Where it comes from |
|---|---|
| Up to 200 hours to improve by one band | How an older IELTS handbook put it for individuals (used until 2002); Cambridge research later concluded such a formula cannot be supported. |
| Average gains of about 0.3 to 0.6 of a band over about three months of course study, with large differences between individuals | Source: IELTS.org, "How long will it take to get the IELTS band score I need?" Based on two studies cited by IELTS.org: one of Korean students in IELTS preparation classes and one of students on intensive English courses in Australia and New Zealand. |
The two studies in a little more detail: Kang et al. (2021) followed 52 students in IELTS preparation classes in Korea, and Elder and O'Loughlin (2003) followed 112 students on intensive English courses at four institutions in Australia and New Zealand. Average gains were about 0.3 of a band in the Korean study and about 0.6 in the Australia and New Zealand study, and individual results varied widely: some students gained a full band or more, and some scored lower the second time.
These figures are averages or general guidance, not a schedule. The same IELTS.org article that cites these two studies also describes one student who studied around 60 hours a week for three months and improved by a full band, and another, who did not enjoy the course and was very anxious about the test, who showed no improvement at all over the same period. Treat every number on this page as a wide range, not a guarantee.
What about a single step, like 5.5 to 6.0 or 6.0 to 6.5?
No source gives a reliable hours figure for a single half-band step (5.5→6.0, 6.0→6.5, 6.5→7.0). In the Australia and New Zealand study, courses had roughly 200-240 hours of classroom instruction over 10-12 weeks and the average gain was about 0.6 of a band. In the Korean study, students reported about 284 hours of study on average over 12 weeks and gained about 0.3 of a band on average. Some students gained a full band or more and some scored lower, and no hours-per-half-band figure can be derived from either study. Treat any hours estimate as a very wide ballpark.
Does your starting band change the pace?
Yes. The two research reports described above point the same way: over a 10-12 week period, students who started at lower bands gained more on average than students who started higher. Part of this pattern may simply be regression to the mean (people who score low on one test tend to score higher on the next, and people who score high may score lower).
- IELTS.org itself reports that the biggest gains happen among students starting below band 5.5 who study more than 23 hours a week and are more motivated.
- In both studies, average gains were smaller the higher students started, so progress tends to be slower at higher starting bands. In the Australia and New Zealand study (Elder and O'Loughlin, 2003), students who started at 4.5 gained 0.71 of a band on average over 10-12 weeks and those who started at 6.0 gained 0.42. In the Korean study (Kang et al., 2021), the averages were 0.7 and 0.32 over 12 weeks. At higher starting bands some students scored lower the second time, and the numbers at the top of the scale were small.
Researchers offer several possible explanations for this pattern: regression to the mean (described above), lower-level learners may benefit more from short periods of instruction, and progress at higher levels may not be well captured by the test. Many learners find that higher bands also depend more on precision, range and naturalness - but that is a practical observation, not a research finding.
What IDP IELTS Vietnam's 2022 articles say
IDP IELTS Vietnam is run by IDP, one of the three IELTS partners - the British Council, IDP IELTS and Cambridge University Press & Assessment. Its articles from 2022 give general estimates that differ from page to page (for example about 5-6 months from zero to 5.0, about 12 months from zero to 6.5, and at least 14 months from zero to 7.5); they are rough guidance, not research findings. Two figures from the article first published in November 2022 come with conditions that are easy to miss:
- Around 1 more month of advanced study to reach 6.5-7.5 - but only for learners who already have the advanced knowledge expected at 5.5-6.5. The article's general rule is 2-4 more months for each additional band.
- 2-4 months of highly focused study to reach 8.0 - but only for learners who are already confident at 7.5.
What kind of study the research describes
The studies behind these figures involved students enrolled in courses (classroom instruction, plus self-reported study hours in the Korean study), not passive exposure to English. That may not translate directly to someone studying alone, so treat these figures as a loose guide rather than a prediction for your own routine.
Finding your own starting point and pace
None of the estimates above are useful until you know two things: which band you are starting from in each of the four skills, and which one is actually holding your overall score down. The IELTS band score calculator converts raw practice-test scores into an estimated band for Listening and Reading and works out an overall band from all four skills, so you can see where you stand before committing to a timeline.
From there, 1:1 sessions target whichever skill is actually short of your goal, instead of moving through a fixed syllabus at a fixed pace. Mike is CELTA-certified (Cambridge), has taught English and IELTS for 12 years across Vietnam, Turkey and Iran, and currently teaches 250 students across 10 classes at Newton Grammar School in Hanoi; his own IELTS result is 7.5 overall with 8.5 in Speaking. Regular 1:1 online IELTS coaching sessions are 500,000 ₫ for 60 minutes in Vietnam, live over Google Meet. If your test date is close and you want more than one session a week, intensive prep before a set test date covers how sessions can be booked closer together instead of spread over months.
The 30-minute trial session is 150,000 ₫ (once per student, on the first booking; students outside Vietnam see their own region's price, in their own currency, on the booking page before paying) - a low-cost way to get an outside read on your starting point and which skill to prioritise, before you plan a longer timeline. Book a trial session in your own timezone.
Band Booster IELTS does not guarantee any band score, outcome or timeline. The figures above are general guidance, not a promise.