Quick answer: DET is cheaper, faster, and fully remote — there's no honest argument against it on those three axes. But DET is not on the UK Home Office's approved SELT list, and LanguageCert is. If your requirement is a UK visa, the price and speed advantages of DET are irrelevant, because it structurally cannot meet that requirement. If your requirement is general academic admission somewhere that accepts either, DET usually wins on cost and convenience.
TL;DR
- LanguageCert is Home Office-approved for UK visas (SELT); DET is not, and isn't on that approved list at all.
- DET costs about $70 with 48-hour results; LanguageCert's SELT variants cost roughly $270 with about 10-business-day turnaround.
- DET is fully computer-adaptive and AI-scored end to end — no live human interlocutor at any point. LanguageCert's Speaking exam is a live ~13-minute session with a real examiner.
- DET is accepted by 6,000+ institutions, historically strongest across the US and Canada. LanguageCert's strength is UK-specific — SELT for all UK visas, plus broad UK university admission acceptance.
1. The UK visa (SELT) reality check
Per the UK government's own guidance, the only approved SELT providers are Trinity College London, the IELTS SELT Consortium, LanguageCert, and Pearson (PSI Services outside the UK). DET does not appear on that list, in the same way Password doesn't. If your actual requirement is a UK student, work, or settlement visa, the comparison below is close to moot — DET cannot satisfy it regardless of your score, and LanguageCert can.
2. Price and speed — DET wins clearly
DET costs about $70, takes 60 minutes, and returns a score within 48 hours. LanguageCert's SELT variants (Academic SELT, General SELT) cost roughly $270; International ESOL pricing varies by country and test centre. LanguageCert's Written exam runs about 2h40 at B2, with a separate ~13-minute Speaking exam, and results typically arrive in about 10 business days.
To be direct about it: if your only requirement is general academic admission somewhere that accepts both tests, DET is objectively cheaper and faster. There's no case for LanguageCert on cost or turnaround alone.
3. Format — live human assessment vs full automation
DET is the most automated of the major English tests: every task — including its speaking tasks — is scored algorithmically, with adaptive difficulty and a strict AI proctor that flags eye movement, other voices in the room, and app-switching. There is no live human interlocutor at any point in a DET sitting.
LanguageCert's Written sections follow a traditional Listening/Reading/Writing format, and its Speaking exam is a live, roughly 13-minute session with a real interlocutor, face-to-face or online. If your institution — or you personally — wants evidence of a live-assessed spoken interaction rather than an algorithmic score, DET structurally cannot provide that; LanguageCert can.
4. Institutional acceptance patterns
DET is accepted by 6,000-plus institutions, with its strongest historical footprint across the US and Canada, and growing acceptance elsewhere. LanguageCert's strength runs the other direction: it's accepted as SELT by all UK universities for visa purposes, with broad direct-admission acceptance across UK Russell Group and post-92 universities specifically.
In practice this means the two tests have different geographic sweet spots — DET for a US/Canada-heavy application list, LanguageCert for anything UK-visa-adjacent — rather than one being a strict upgrade of the other.
5. Decision table
| Factor | LanguageCert | DET |
|---|---|---|
| UK visa (SELT) eligible | Yes | No |
| Price | ~$270 (SELT); varies by country (ESOL) | ~$70 |
| Results turnaround | ~10 business days | 48 hours |
| Speaking assessment | Live interlocutor, ~13 min | Fully AI-scored, no live human |
| Institutions accepting | All UK unis (visa); broad UK admission acceptance | 6,000+, strongest in US/Canada |
6. When to choose which
Choose DET when: your target list is mostly US or Canadian institutions, cost and turnaround matter most, and a UK visa isn't part of the requirement.
Choose LanguageCert when: you need UK SELT eligibility, you want a live-assessed speaking score rather than an algorithmic one, or your route is UK-specific — admission, pre-sessional, or visa.
For the full LanguageCert format, scoring and prep timeline, see the LanguageCert Complete Guide. For skill-specific prep, see Speaking strategy and Listening strategy. To see how both stack up against IELTS, PTE, TOEFL and more, see the full 8-exam cost comparison.
Frequently asked questions
Is DET accepted for a UK student visa? No. The Duolingo English Test does not appear on the UK Home Office's approved Secure English Language Test (SELT) provider list, which currently names only Trinity College London, the IELTS SELT Consortium, LanguageCert, and Pearson. DET cannot currently be used to meet a UK visa's English-language requirement, regardless of your score.
Is DET cheaper than LanguageCert? Yes, substantially. DET costs about $70; LanguageCert's SELT variants cost roughly $270, with International ESOL pricing varying by country. If cost is your only constraint and a UK visa isn't a factor, DET is clearly cheaper.
Does DET have a live speaking component? No. Every DET task, including its speaking tasks, is scored algorithmically with no live human interlocutor at any point. LanguageCert's Speaking exam is a live session of about 13 minutes with a real examiner, face-to-face or online.
Which test returns results faster? DET returns results within 48 hours of a 60-minute test. LanguageCert takes about 10 business days across its longer Written and Speaking exams. If a deadline is close and DET is accepted by your target institution, its speed is a real advantage.
Can I use LanguageCert or DET interchangeably for the same UK university offer? Only if your offer letter explicitly names both as acceptable — check it directly. Many UK admissions pages don't list DET at all, while LanguageCert appears on UK acceptance lists specifically because of its SELT status.