Introduction: Why Your Setup Matters as Much as Your English
The Duolingo English Test (DET) is taken at home, on your own computer, which means you — not a test center — are responsible for every piece of hardware, software, and lighting in the room. Since late 2025, the requirements have gotten noticeably stricter: a mandatory second camera, a 360° room scan, and an ear check now happen before the adaptive test even starts. Skip one of these steps, and even a perfect English score won't save your session from invalidation. This checklist covers exactly what's required in 2026, based on Duolingo's current setup process, so you walk in prepared.
1. Device and Operating System
Not every computer qualifies. The DET runs through a dedicated desktop app, not a browser, so your device needs to support it.
| Requirement | Details |
|---|---|
| Device | Windows or Mac laptop/desktop only. Phones, tablets (including iPad), Chromebooks, and Linux machines are not supported. 2-in-1 devices like Surface Pro may not work reliably. |
| Operating System | Windows 10 or later, or macOS 10.15 (Catalina) or later. |
| Application | The official DET desktop app, downloaded after you purchase your test. It is not taken inside a browser tab. |
| Monitor | Single monitor only — a second screen is treated as an integrity risk and is not allowed. |
| Peripherals | One mouse and one keyboard. You can't switch input devices mid-test. |
2. Camera, Microphone, and Internet
| Component | Requirement | Why It Matters |
|---|---|---|
| Primary Webcam | Front-facing, built-in or USB, positioned near eye level. | Used for identity verification and continuous face/gaze monitoring. |
| Microphone | Built-in or external. It cannot be part of a headset. | Records your speaking tasks and picks up background sound. |
| Speakers | Built-in or external. Headphones or earbuds that cover your ears are not allowed. | Proctors need to verify you aren't receiving outside audio help. |
| Internet Speed | Minimum 2 Mbps download / 1 Mbps upload. 10 Mbps or faster is recommended, and wired Ethernet is strongly preferred over Wi-Fi. | A dropped connection mid-test can end your session before it's complete. |
3. The Secondary Camera Requirement (Mandatory Since September 2025)
This is the single biggest change test takers miss, and it's why most 2024-era guides — including older versions of this article — are now out of date. Every DET session requires a smartphone or tablet positioned beside your computer as a second camera. There is no way to start the test without completing this step.
Your phone records your screen, keyboard, and upper body from a side angle for the entire session, and that footage is cross-checked against your primary webcam recording. It's designed to catch remote-access cheating, where someone else controls your screen from another location.
- What you need: a smartphone or tablet (not a second laptop) with a charged battery or a charger plugged in, connected to Wi-Fi, with Do Not Disturb turned on and the official DET mobile app installed.
- Setup: scan the QR code shown in the desktop app, enter the confirmation code on your phone, then lay the phone horizontally to the left or right of your computer using a stable support (a stand or a stack of books works) so your full screen, keyboard, and upper body stay in frame.
- During the test: do not touch, move, or pick up the phone again once you begin. If it falls or the recording is interrupted, you may need to quit and restart from the beginning.
4. Room Scan and Ear Scan
Before the adaptive section begins, your phone camera walks through two checks:
- 360° room scan: point the phone at your computer, rotate a full circle while keeping the on-screen arrow centered, then point it down at your keyboard and the area behind your laptop.
- Ear scan: briefly hold the phone up to each ear to confirm you aren't wearing earbuds or any hidden audio device.
5. Software to Close Before You Start
Run these checks the morning of your test, not the night before — software updates can quietly reappear overnight:
- Close every browser window, browser extension, and writing assistant (Grammarly and similar tools will block your session if active).
- Quit any VPN — this causes immediate invalidation, not just a warning.
- Close remote-access or screen-sharing software (TeamViewer, AnyDesk, Zoom, etc.) and any third-party keyboard or clipboard tools.
- Pause background sync services that might trigger pop-up notifications mid-test.
6. Environment Setup
Only three things are allowed on your desk once the room scan starts: your computer, your phone in its secondary-camera position, and your ID.
- Alone in the room: anyone entering, even briefly, can invalidate your session.
- Lighting: put a lamp in front of you, not behind you — backlighting creates a silhouette that fails identity checks.
- Clear desk: no notebooks, papers, pens, extra devices, or smartwatches.
- Quiet room: occasional background noise is generally tolerated, but any conversation directed at you is a violation.
7. The Most Common Reasons Tests Get Invalidated
According to Duolingo's own guidance, these six issues account for most invalidations — and nearly all of them are avoidable with the setup above:
- Frequent gaze diversion — eyes repeatedly leaving the screen, even just to think
- Someone entering the room or speaking to you during the test
- Background software running (VPNs, remote-access tools, browser extensions)
- Copy-pasting text — any detected copy action triggers automatic invalidation
- Unauthorized items on the desk
- Improper secondary-camera placement that doesn't capture your full screen and keyboard
8. Registration, Cost, and Retakes
- Cost: around $65–70 USD per attempt — confirm the exact price for your region at checkout, as it varies.
- Test window: you have 21 days from purchase to start your test.
- Retake limit: up to 2 certified attempts within any rolling 30-day window; invalidated attempts still count toward that limit.
- Results: typically within 48 hours, valid for 2 years, with free and unlimited score sending to institutions.
- Appeals: a 72-hour window from when you receive your result.
9. Frequently Asked Questions
Can I take the DET on a Chromebook, iPad, or Linux computer?
No. The desktop app only supports Windows 10+ and macOS 10.15+. Chromebooks, tablets, phones, and Linux systems are not compatible.
Do I really need a second phone or tablet to take the test?
Yes. Since September 2025 the secondary camera is mandatory for every test taker — there's no opt-out. A second laptop cannot substitute for it, though a borrowed phone or tablet is fine.
Can I wear headphones during the test?
No. Your microphone and speakers must be separate from any headset, and headphones or earbuds that cover your ears aren't permitted — this is part of what the ear scan checks for.
What internet speed do I actually need?
Duolingo's stated minimum is 2 Mbps download and 1 Mbps upload, but 10 Mbps or faster over a wired connection gives you a much larger safety margin against drops.
What happens if my test gets invalidated?
It depends on the severity: a rule violation may let you retake with remaining credits (no refund, no appeal); possible misconduct expires your credit but allows a 72-hour appeal; confirmed misconduct results in a permanent ban with one final appeal.
10. Practice Under Real Conditions on Prepingo
Reading a checklist and testing under proctoring pressure are two different things. Prepingo's mock tests replicate the DET's adaptive format and timing so you can practice speaking and writing responses under a live timer, then get instant feedback on grammar, vocabulary range, and task relevance before you spend $65–70 on the real thing.