How Many Duolingo English Test Practice Tests Should You Take? What Research on 25,969 Students Reveals
If you're preparing for the Duolingo English Test (DET), you've probably wondered how many practice tests you should complete before booking the real exam. Should you take two or three? Five? Ten? And will completing more practice tests actually improve your score?
A large research study involving 25,969 DET test takers offers some surprising insights. Students who completed one to three official practice tests achieved higher average certified scores than those who completed none or four or more. However, the results reveal something more important than an ideal number: the difference between becoming familiar with an examination and genuinely improving your English.
Let's examine what the researchers discovered, what the findings mean for your preparation, and how to decide when you're ready for the official DET.
🚫 5 Reasons You Should Never Attempt to Cheat on the Duolingo English Test
What Did the Research Actually Find?
In October 2025, researchers published a study titled Exploring AI-Enabled Test Practice, Affect, and Test Outcomes in Language Assessment. The research examined the relationship between practice-test frequency, official DET performance, test-taker confidence, and score-sharing behavior.
The study analyzed 25,969 first-time test takers who received certified DET scores. Researchers examined how many official practice tests participants completed during the 60 days preceding their examination.
The results revealed a clear pattern.
| Practice tests completed | Number of students | Average certified DET score |
|---|---|---|
| 0 | 4,742 | 108.5 |
| 1 | 6,128 | 112.4 |
| 2–3 | 6,469 | 112.3 |
| 4–6 | 4,142 | 111.1 |
| 7 or more | 4,488 | 108.6 |
Source: Burstein et al. (2025), Table 3. Read the original research.
Students who completed just one practice test averaged 112.4 on their certified examination. Those completing two or three achieved a nearly identical average of 112.3. Interestingly, students taking seven or more practice tests averaged 108.6, almost the same as students who took none.
At first glance, these results might suggest that students should stop taking practice tests after their third attempt. But that would be the wrong conclusion.
The study identified an association, not a cause-and-effect relationship. Taking additional practice tests was not proven to lower scores, and completing exactly three was not established as the ideal preparation strategy for every student.
Why More Practice Tests Don't Automatically Mean Higher Scores
Imagine two students preparing for the DET. The first already has strong English skills but wants to understand the examination format. After completing two practice tests and reviewing the question types, the student feels ready.
The second student needs a DET score of 130 but consistently receives estimated practice ranges below that target. This student completes eight practice tests, hoping that repetition will eventually produce a higher score.
Which student is likely to perform better on the official examination?
The answer depends primarily on their English proficiency, not simply how many practice tests they've completed.
The researchers suggested that students who take many practice tests may be using them for purposes beyond test familiarization, such as attempting to develop language skills or discover test-taking strategies. Students who find the examination difficult may also be more motivated to repeat it.
These possibilities help explain the findings without suggesting that additional practice tests are harmful.
For a broader introduction to building your preparation routine, DET Study's guide to improving your Duolingo English Test preparation explains how test familiarity, speaking, writing, vocabulary, and grammar practice fit together.
What Is the Official DET Practice Test Designed to Do?
The official Duolingo English Test practice test is free and can be completed as many times as you want. According to the DET Help Center, it takes approximately 45 minutes and includes the same question types and adaptive testing approach used in the certified examination.
After completing the practice test, you receive an estimated score range rather than a guaranteed certified score. This range helps you understand your current proficiency and whether you may be ready for the official examination.
For example, suppose your practice score range is 115–125 and your university requires 120. That result suggests you're approaching the requirement, but it doesn't guarantee you'll achieve 120 on test day.
If your university requires 135, the same practice range tells you something different: you probably need additional preparation before relying on a certified result.
The official practice test is therefore especially useful for answering two questions: Am I familiar with the test format, and does my estimated performance suggest I'm ready for my target score?
It is not designed to replace the broader language development needed to move from one proficiency level to another.
Lance Graney
Watch: Build Your DET Preparation Skills
Full practice tests are only one part of preparing effectively. Understanding individual question types and practicing your responses can help you use the time between mock tests more productively.
The Difference Between Taking Practice Tests and Actually Practicing
This distinction is probably the most important lesson from the research.
A full-length practice test measures how you perform across multiple English skills under examination-style conditions. Targeted practice concentrates on improving particular skills that may be holding back your performance.
Both activities are useful, but they serve different purposes.
Consider a student who struggles with Interactive Listening. Completing another entire practice test might confirm that listening remains a weakness. However, focused listening exercises, vocabulary development, and summarization practice may be more productive between assessments.
The same principle applies to reading, speaking, and writing.
Speaking: Develop Clearer, More Natural Responses
Students who struggle with speaking questions sometimes assume that they need to memorize more advanced vocabulary. In reality, effective spoken communication also depends on responding directly to the prompt, organizing ideas, using appropriate grammar, and speaking intelligibly.
A useful exercise is to record a response to a timed prompt, listen to it, and identify one or two specific weaknesses. You might notice that your response lacks supporting details, contains repeated grammatical errors, or becomes difficult to follow when you speak too quickly.
Writing: Improve Accuracy and Organization
Writing preparation follows a similar pattern. Students often concentrate on producing longer answers without evaluating whether their sentences are accurate or their ideas are logically connected.
A stronger approach is to practice developing a clear main idea, adding relevant supporting information, and reviewing grammar and vocabulary choices.
For example, compare these two responses to a photograph:
Basic response: "There is a woman in a park. She is walking. The weather is nice."
More developed response: "A woman is walking along a tree-lined path in a quiet park. The bright sunlight and clear sky suggest that she is enjoying a pleasant afternoon outdoors."
The second response provides more relevant visual detail and demonstrates a wider range of sentence structures. It is not automatically guaranteed a particular score, but it offers a useful example of how to develop a description.
If photo-description tasks are difficult for you, DET Study's guide to useful phrases for describing photos provides examples of language for describing position, movement, scenery, and visual details.
Reading and Listening: Build Comprehension Between Tests
Reading and listening improvement often requires sustained exposure to English rather than repeated full-length examinations.
For reading, practice understanding short passages, identifying main ideas, recognizing vocabulary in context, and interpreting sentence relationships. For listening, concentrate on understanding spoken information, remembering important details, and distinguishing central ideas from supporting information.
These activities help develop the language abilities that the DET is designed to assess.
A student who spends several days strengthening comprehension may gain more useful preparation than someone who completes several mock tests without reviewing the difficulties they encounter.
A Practical DET Preparation Plan
So how many practice tests should you actually take?
A reasonable starting approach is to take one official practice test to establish your baseline, focus on your weaknesses, and then take another to reassess your readiness. A third test may help you check consistency, but there is no research-backed rule requiring you to stop there.
Here's an example of how to organize a week of preparation.
| Day | Preparation activity | Main objective |
|---|---|---|
| Day 1 | Official DET practice test | Establish your estimated score range |
| Day 2 | Review difficult question types | Identify weaknesses |
| Day 3 | Speaking and writing practice | Improve response quality |
| Day 4 | Reading and listening exercises | Strengthen comprehension |
| Day 5 | Timed question-type practice | Improve familiarity and consistency |
| Day 6 | Second official practice test | Reassess overall readiness |
| Day 7 | Review results and decide next steps | Prepare further or consider booking |
This is an illustrative study schedule, not a schedule validated by the research. Students with larger gaps between their current proficiency and target score may need several weeks or months rather than seven days.
The key is to give yourself time to develop the skills identified as weak before repeatedly measuring them again.
