What Is Prepingo?
Prepingo is a DET preparation platform built specifically for the Duolingo English Test. It gives you two things: unlimited free practice questions across every DET question type, and — for test-takers who want real feedback — an AI evaluation system that scores your writing with an estimated band score, CEFR level, and a detailed four-tab analysis that breaks down exactly what is holding your score back.
Practice is permanently free — no question cap, no time limit, no credit system. The AI assessment requires a premium subscription. You practice for free as long as you want; you subscribe when you want to know your score estimate and get the detailed feedback that tells you what to fix.
Free vs Premium: What You Get at Each Level
| Feature | Free Plan | Premium Plan |
|---|---|---|
| Practice questions | ✅ Unlimited — all 13 question types | ✅ Unlimited — all 13 question types |
| Mock Test | ✅ Available | ✅ Available |
| Attempt History | ✅ Per question | ✅ Per question |
| Progress Dashboard | ✅ Full access | ✅ Full access |
| Study Plan | ✅ Full access | ✅ Full access |
| Leaderboard | ✅ Full access | ✅ Full access |
| Community | ✅ Full access | ✅ Full access |
| Vocabulary section | ✅ Full access | ✅ Full access |
| Sticky Notes | ✅ Full access | ✅ Full access |
| AI Overall Band Score | ❌ Premium only | ✅ Every evaluation |
| CEFR Proficiency Level (B1/B2/C1/C2) | ❌ Premium only | ✅ Every evaluation |
| AI Feedback paragraph (Overview tab) | ❌ Premium only | ✅ Every evaluation |
| Score Breakdown — Content / Grammar / Coherence / Lexis | ❌ Premium only | ✅ Scores tab |
| Smart Tutor — Grammar Tutor with individual error drill | ❌ Premium only | ✅ Smart Tutor tab |
| Estimated Score After Fix | ❌ Premium only | ✅ Smart Tutor tab |
| Fix All + Submit Re-Evaluation | ❌ Premium only | ✅ Smart Tutor tab |
| Tips tab — personalized improvement bullet points | ❌ Premium only | ✅ Tips tab |
How Prepingo Works: The Complete Practice-to-Feedback Workflow
Here is the full process from opening a question to receiving AI feedback, using Write About the Photo as the example.
Step 1 — Open a Practice Question
From the sidebar, click Practice. Select a question type from the full DET question list. A question loads with the authentic DET interface: the image on the left, a description input field on the right, and a live countdown timer in the top right corner (60 seconds for Write About the Photo). Above the input field you can see the time limit, minimum sentence requirement (1+ SENT.), and a live word counter.
The timer starts the moment the question loads — exactly as it does on the real DET. You can also review your Attempt History for any question using the button beside the timer, so you can compare your current response to previous attempts on the same question.
Step 2 — Write Your Response and Submit
Type your response in the Description Input field. The word counter updates live. When finished, choose one of two paths:
- Submit Evaluation — submits your response for full AI analysis. Requires a premium subscription for the detailed feedback.
- Skip AI — records your attempt and moves to the next question without consuming an AI evaluation. Available on the free plan for unlimited use.
Step 3 — AI Analysis: Overview Tab
After submitting, Prepingo's AI engine processes your response. The Writing Analysis screen loads with four tabs across the top: Overview, Scores, Smart Tutor, Tips.
The Overview tab shows first, displaying two headline results:
- Overall Band — your estimated DET score for this response (e.g., 85, 95, 110, 125). This is the score your writing would receive on the real exam as evaluated by Prepingo's AI.
- CEFR Proficiency Level — your current level shown as B1, B2, C1, or C2. A score of 85 maps to B1; a score of 115+ maps to B2/C1; a score of 130+ is solid C1.
Below the CEFR card, the context image you described is displayed, followed by an AI Feedback paragraph — a plain-English summary of what your response did well and what its main weakness was. For example: "The student demonstrates a good ability to identify and describe key elements in the photo, and they successfully met the word count requirement. However, the frequent grammatical errors, particularly with subject-verb agreement and verb forms, significantly impact the clarity and overall quality of the writing. Addressing these foundational grammatical issues will greatly improve their written communication."
At the bottom of the Overview tab, three navigation buttons appear: Next Question (loads the next practice question), Pick for Me (Prepingo selects the next question based on your performance data), and Close.
Step 4 — Scores Tab: Four-Dimension Breakdown
Click the Scores tab to see your Score Breakdown across four independent dimensions. Each is rated on a scale from Developing → Needs Work → Good → Excellent, with a detailed explanation of what specifically was strong or weak:
| Dimension | What It Evaluates | Rating Scale |
|---|---|---|
| Content | Whether you accurately described the image, identified the main subject, went beyond simple labeling, made inferences, and met the word count | Developing / Good / Excellent |
| Discourse Coherence | Whether your response flows logically, uses spatial language to connect observations, and transitions smoothly between ideas | Developing / Good / Excellent |
| Grammar | Subject-verb agreement, verb tense and form, articles, sentence structure — the mechanical accuracy of your writing | Needs Work / Developing / Good / Excellent |
| Lexis | Vocabulary range, specificity, and sophistication — whether you use precise, varied, C1/C2 words or generic basic vocabulary | Developing / Good / Excellent |
Each card gives a specific written explanation, not just a label. For Grammar rated Needs Work, a typical card reads: "There are numerous grammatical errors, primarily with subject-verb agreement ('picture show', 'He wear', 'weather look', 'person are', 'everything seem', 'image give', 'would likes'), verb tense/form ('is cover', 'is rise'), and incorrect use of 'There have' instead of 'There are'. These errors significantly hinder overall fluency and accuracy."
This level of specificity tells you exactly which error patterns to fix — not just that your grammar "needs work."
Step 5 — Smart Tutor Tab: Grammar Tutor + Score Projection
The Smart Tutor tab is where score improvement actually happens. It contains the Grammar Tutor — the most actionable part of the entire evaluation.
Your original response is displayed with every error highlighted in red. The Grammar Tutor header shows the total issue count (e.g., "14 total issues") and the breakdown by type: Grammar (13) and Lexical (1). A progress bar fills from left (grammar) to right (lexical) showing the proportion of each error type.
You can toggle between Original view (errors highlighted) and Corrected view (clean version with all fixes applied) at any time.
Each error is addressed individually in sequence (1/14, 2/14, 3/14...):
- The original error is shown crossed out in red (e.g., "This picture show")
- The corrected version is shown in green beside it (e.g., "This picture shows")
- A plain-English grammar explanation explains the rule (e.g., "Subject-verb agreement: 'picture' is singular, so the verb needs an '-s' in the present simple tense.")
- A "Retry by typing..." input field lets you type the correction yourself — active recall, not passive reading
- A "Save this fix" button records your correction before moving to the next error
- Navigation arrows (◁ ▷) let you move between errors at your own pace
This is not a corrections list to read and forget. It is an active drill — you understand the rule, type the fix yourself, and save it before moving on. This is the same principle behind effective language learning: active production beats passive recognition for retention.
At the bottom of the Smart Tutor tab, three persistent elements are visible:
- Estimated Score After Fix — the band score your response would receive if all identified errors were corrected. In the example screenshots, a response that scored 85 had an Estimated Score After Fix of 115 pts. That 30-point gap is the direct numerical cost of grammar errors on this response.
- Fix All — applies all corrections automatically in one click if you want to see the cleaned version immediately.
- Submit Re-Evaluation — sends your corrected response back to the AI for a new score. This shows you the actual score once grammar is no longer the bottleneck — revealing whether vocabulary and sentence structure are the next constraints to work on.
Step 6 — Tips Tab: Personalized Improvement Actions
The Tips tab is the fourth and final evaluation tab. It contains a set of personalized Improvement Tips based on the specific errors and weaknesses identified in your response — not generic advice, but actions targeted to your actual mistakes.
For example, after a response with subject-verb agreement errors and basic vocabulary, the Tips tab would show:
- "Review and practice subject-verb agreement rules, especially for third-person singular present simple tense (e.g., 'he wears', 'it shows')."
- "Pay close attention to verb forms and tenses, ensuring correct usage (e.g., 'is covered' instead of 'is cover', 'is rising' instead of 'is rise')."
- "Expand vocabulary with more descriptive adjectives and adverbs to provide richer and more nuanced details about the image."
These tips give you a specific practice agenda for your next session — which grammar rules to study, which vocabulary areas to expand, and which structural habits to build. After reviewing the tips, click Next Question to continue practicing, or Pick for Me to let Prepingo select the next question based on your performance data.
Mock Test: Full DET Simulation
Beyond individual question practice, Prepingo includes a Mock Test section that replicates the full DET format — question sequence, question types, and timing. Use it to check overall readiness rather than practice a specific skill.
Use the Practice section for daily targeted work on specific question types. Use the Mock Test when you want to know whether you are ready to book the real exam. Run at least two full mock tests before your test date — one to baseline, one to confirm improvement after your preparation period.
All Features Available on Prepingo
- Progress Dashboard — tracks your practice history over time. See which question types you have covered, how frequently you practice, and how your performance trends over weeks.
- Study Plan — a built-in structured preparation roadmap. Instead of deciding each session what to practice, the Study Plan allocates your time based on your progress data.
- Leaderboard — shows your ranking relative to other Prepingo users by practice volume and performance.
- Vocabulary Section — a dedicated vocabulary builder for DET-relevant academic words. Directly addresses the Lexis dimension of the AI scoring rubric.
- Community — a shared space for test-takers to discuss questions, compare responses, and share preparation strategies.
- Sticky Notes — in-platform notes you can attach to sessions. Useful for logging recurring error patterns you notice across multiple evaluations.
- Attempt History — every question shows previous attempts. Compare responses over time to see whether your grammar accuracy and vocabulary are measurably improving between sessions.
- Pick for Me — after completing a question, click this to let Prepingo select your next question automatically based on your performance profile.
How to Use Prepingo Effectively: 4-Week Practice Structure
| Week | Focus | Daily Prepingo Session (30–45 min) |
|---|---|---|
| Week 1 | Diagnostic + format familiarity | Practice 3–5 questions from each question type. Run one Mock Test at the end of the week. Note your two weakest question types. |
| Week 2 | Targeted skill building | Focus daily sessions on your two weakest question types. Use AI evaluation on all writing responses. Read every Scores tab card in full. |
| Week 3 | Grammar repair + vocabulary expansion | Work through the full Smart Tutor drill for every evaluated response — all 14 issues individually, not just "Fix All." Use the Tips tab to set your agenda for the next session. Study Vocabulary section for 10 minutes per day. |
| Week 4 | Full simulation + confirmation | Run two Mock Tests. Practice 3 Write About Photo + 2 Interactive Writing per day with AI scoring. Use Attempt History to confirm improvement vs Week 1 baseline. |
Who Prepingo Is Best For
| Your Situation | What to Use |
|---|---|
| Just starting, not sure of your level | Free plan — run a Mock Test first, then practice the hardest question types |
| Building daily practice volume | Free plan — unlimited questions, all types, no cap |
| Want to know your score before booking the real DET | Premium — AI gives Overall Band + CEFR on every writing response |
| Stuck between 100–115 and can't push higher | Premium — Smart Tutor identifies exactly which grammar patterns are capping your score |
| Score is 115+ and targeting 130+ | Premium — use Submit Re-Evaluation after grammar correction to see your vocabulary ceiling; use Tips tab to expand lexical range |
| Test is in 7 days | Premium — Mock Test today, AI evaluation on writing, full Smart Tutor drill, another Mock Test 3 days before exam |
Start Practicing Free — No Account Required to Begin
Go to Prepingo app to start immediately. Practice is always free — no credit card, no trial period, no question cap. Create an account when you want to save your progress and access the Study Plan. Subscribe when you want AI scoring, your band score estimate, and the four-tab feedback system that shows you exactly what is costing you points.
The most common reason test-takers waste a $70 DET credit is sitting the real exam without knowing where their score stands. Prepingo's Estimated Score After Fix gives you that number before you book — so you only take the real exam when you are ready.
Frequently Asked Questions
Is Prepingo free for DET practice?
Yes — practice questions are permanently free with no cap. You can practice every DET question type, run mock tests, use the Study Plan, and track your progress without paying. The AI Writing Analysis — band score, CEFR level, four-tab feedback (Overview / Scores / Smart Tutor / Tips) — requires a premium subscription.
Can Prepingo estimate my Duolingo score before the exam?
Yes. With a premium subscription, the AI Writing Analysis gives you an Overall Band score estimate and CEFR proficiency level for every writing response. The Smart Tutor tab also shows an Estimated Score After Fix — the band score your response would receive once all grammar errors are corrected, giving you both your current score and your ceiling.
What is the Smart Tutor on Prepingo?
The Smart Tutor is the third tab in Prepingo's four-tab Writing Analysis. It contains the Grammar Tutor — a drill that shows every error in your response, counts them by type (Grammar vs Lexical), and walks you through each one individually: original (crossed out in red) → corrected (shown in green) → plain-English rule explanation → retry by typing → save the fix. At the bottom it shows your Estimated Score After Fix and gives you Fix All and Submit Re-Evaluation options.
What is the Tips tab on Prepingo?
The Tips tab is the fourth tab in the Writing Analysis. It shows personalized Improvement Tips based on the specific errors in your response — not generic advice, but targeted actions like which grammar rules to practice and which vocabulary areas to expand, derived from your actual mistakes in that session.
What question types can I practice on Prepingo?
All 13 DET question types: Write About the Photo, Interactive Writing, Writing Sample, Interactive Speaking, Speaking Sample, Speak About the Photo, Listen and Type, Listen and Complete, Interactive Listening, Read and Select, Read and Complete, Fill in the Blanks, and Interactive Reading. All unlimited and free.
How is Prepingo different from Arno?
Both offer free unlimited practice and AI scoring. Prepingo's specific advantages: CEFR level shown alongside band score, a four-tab feedback system (Arno uses a single view), Smart Tutor requiring active typing corrections rather than passive reading, Estimated Score After Fix shown numerically, Submit Re-Evaluation after correction, a Tips tab with personalized improvement actions, a Pick for Me feature, and a built-in Study Plan. Arno has a larger question bank (30,000+) and is a Duolingo Platinum Partner.
Is there a mock test on Prepingo?
Yes — the Mock Test section simulates a full DET with the real format, question sequence, and timing. Use it to check overall readiness before your exam date. Use Practice for targeted daily skill work.
What does "Estimated Score After Fix" mean on Prepingo?
It is the projected band score your response would receive if all grammar and lexical errors identified by the Smart Tutor were corrected. It appears at the bottom of the Smart Tutor tab. The gap between your current Overall Band and the Estimated Score After Fix tells you exactly how many points grammar errors are costing you — and whether fixing grammar alone is enough to reach your target score, or whether vocabulary and structure need work too.