The TOEFL iBT is a 3-hour proctored exam costing around $200, accepted by virtually all U.S. boarding schools, with most requiring a minimum score of 80–100. The Duolingo English Test (DET) is a 1-hour online test costing $70, accepted by most but not all schools, with typical minimums of 105–120. The TOEFL is the safer choice if acceptance is uncertain; the DET is faster, cheaper, and can be retaken more easily.
Knowing which one to take can affect both your preparation timeline and your results.
Acceptance: check first
Before comparing the tests themselves, verify which your target schools accept. Most boarding schools now accept both, but some still require the TOEFL specifically. Check each school’s admissions page carefully. If even one of your target schools does not accept the DET, the TOEFL is your answer.
Score requirements at a glance
| School tier | TOEFL iBT minimum | Duolingo minimum |
|---|---|---|
| Most selective schools | 90–100 | 110–120 |
| Highly selective | 80–90 | 100–110 |
| Selective | 75–85 | 90–105 |
These are approximate ranges. Always confirm the specific requirement with each school.
TOEFL vs Duolingo at a glance
| Feature | TOEFL iBT | Duolingo English Test |
|---|---|---|
| Duration | ~2 hours | ~1 hour |
| Cost | $185–$245 | $70 |
| Where | In-person test center | At home, online |
| Score range | 0–120 | 10–160 |
| Results | 4–8 days | Within 2 days |
| Retakes | Every 3 days, up to 5x/year | Every 30 days, up to 3x/year |
| Acceptance | Virtually all boarding schools | Most, but not all |
| Prep resources | Extensive (books, courses, tutors) | Growing but limited |
| Best for | Students who prefer structured formats; schools that require it | Students who need convenience, lower cost, or faster results |
Format comparison
TOEFL iBT
- Duration: Approximately 2 hours
- Sections: Reading, Listening, Speaking, Writing
- Delivered: At a certified test center (in-person)
- Score scale: 0–120 (four sections, each 0–30)
- Results: 4–8 days
- Cost: Approximately $185–$245 (varies by country)
- Retakes: Can retake every 3 days, up to 5 times per year
Duolingo English Test
- Duration: Approximately 1 hour
- Sections: Adaptive literacy section + video interview + writing sample
- Delivered: At home, via webcam
- Score scale: 10–160
- Results: Within 2 days
- Cost: $70 per attempt ($59 each in a two-test bundle)
- Retakes: Can retake every 30 days, up to 3 times per year
Key differences to know
1. Test center vs. at home
The TOEFL requires travel to an official test center. According to ETS (Educational Testing Service), the TOEFL iBT is administered at over 4,500 test centers in more than 200 countries, but availability varies widely. In many countries this is straightforward; in others it involves long travel or limited availability. The DET can be taken from home on any computer with a webcam, a major practical advantage for students in regions with few test centers.
2. Adaptive format (DET)
The Duolingo English Test adapts to the student’s responses in real time, making it shorter than the TOEFL but harder to “pace” in the traditional sense. It tests a broader range of skills in a less structured format, which some students find more natural and others find unsettling.
3. Cost
The DET at $70 per attempt is much cheaper than the TOEFL (and $59 each if you buy a two-test bundle). For students who may need to retake, the cost difference adds up: three TOEFL attempts cost over $600 in most markets, versus $210 for three DET attempts. This cost should factor into your overall boarding school budget planning.
4. Credibility and familiarity
The TOEFL has been the standard for decades — ETS reports that over 35 million people worldwide have taken the TOEFL since its inception, and it is accepted by more than 12,000 institutions globally. Some admissions officers have deep familiarity with what a given score means in context. The Duolingo English Test launched in 2016 and gained significant adoption during the COVID-19 pandemic; it is now accepted by over 5,000 programs worldwide. This gap in institutional familiarity is narrowing, but families applying to schools where they want every possible advantage may prefer the more established test.
5. Preparation resources
TOEFL has a much larger ecosystem of prep materials – official practice tests, prep books, tutors, and online courses. DET preparation resources are growing but remain thinner. If your student benefits from structured preparation, TOEFL may be the easier test to prepare for effectively.
Which should your student take?
Take the TOEFL if:
- One or more target schools require it
- Your student performs better in structured, predictable test formats
- Access to a test center is not an obstacle
- You want a test result with broad credibility
Take the Duolingo English Test if:
- All target schools accept it
- Test center access is difficult or expensive
- Your student is comfortable with adaptive, conversational formats
- You need a quick turnaround on results (e.g. applying late in the cycle)
- Cost is a significant factor
Consider taking both if:
- Your list includes schools with different requirements
- Your student is a strong English speaker and the additional cost is manageable
- You want to maximize flexibility in how you present scores
When to test
International students should plan to take their English proficiency test at least 3–4 months before application deadlines – ideally earlier. Our complete international student guide includes a full timeline. This allows time for at least one retake if scores fall below target. Since most boarding school applications are due in January, that means sitting the test by October at the latest, and September if possible.
Do not attempt to prepare for both SSAT/ISEE and English proficiency tests simultaneously without a structured plan. The cognitive and time demands are real.
What we’ve seen with international families
We worked with a student from South Korea who took the TOEFL twice and scored 78 both times, just below her target schools’ 80 minimum. She switched to the Duolingo English Test and scored 115 on her first attempt. The adaptive format suited her better: she was a strong conversational English speaker who froze in the rigid TOEFL structure.
Another student, from Brazil, had the opposite experience. He preferred the predictability of the TOEFL’s section-by-section format and found the DET’s adaptive questions disorienting. He scored 95 on the TOEFL after targeted prep.
Neither test is harder. They measure slightly different things in different ways, and the right choice depends on your student.
What to do next
Check your target schools’ requirements first. If they all accept both tests, have your student try a practice version of each. For the TOEFL, use the free practice test at ETS.org. For the DET, Duolingo offers a free practice test at englishtest.duolingo.com. If you need help building a testing and application timeline, book a free consultation. We work with international families regularly.