Offers broad multilingual AI detection and text humanization, but lacks GPTZero's detailed deep-scan reporting features.
Offers broad multilingual AI detection and text humanization, but lacks GPTZero's detailed deep-scan reporting features.
GPTZero records 23,246,989 monthly visits with +32.5% month-over-month growth and Freemium, Paid pricing. OETStudy records 4,738 monthly visits with +264.2% growth and Free pricing.

AI-powered practice and scoring for the Duolingo English Test
| Dimension / Metric | ![]() | |
|---|---|---|
| Official Domain | gptzero.me | oetstudy.com |
| Pricing Model | Freemium, Paid | Free |
| Monthly Visits | 23.25M (23,246,989) | 4.74K (4,738) |
| MoM Traffic Delta | +5.7M (+32.5%) | +3.44K (+264.2%) |
| Primary Market & Share | 🇺🇸 United States (54%) | 🇺🇸 United States (100%) |
| Direct Visits / mo | 7.53M | 1.54K |
| User Rating | 4.1 | 4.4 |
| Supported Platforms | Website | Website |
AI detection and writing verification built for schools and editors
Paste text or upload a document and get an overall AI probability score plus a sentence-by-sentence breakdown of which parts look machine-written.
Flags AI text from major model families including ChatGPT, Gemini, Claude, Llama, and others, rather than training for a single model.
A Chrome extension and Google Docs add-on bring scanning into Gmail, Docs, Classroom, and other surfaces you already work in.
Checks content for copied passages from outside sources so you can separate AI-generation questions from originality questions.

AI-powered practice and scoring for the Duolingo English Test
A large bank of DET-style items spanning speaking, writing, listening, and reading, graded by difficulty so you can practise at the level you need.
Speaking and writing submissions are scored automatically, evaluating pronunciation, fluency, grammar, and content structure with suggestions for improvement.
Check your vocabulary level against CEFR bands and build word lists clustered around the question types you practise most.
Practice statistics and score analysis highlight weak areas and show how your performance changes over time.
Offers broad multilingual AI detection and text humanization, but lacks GPTZero's detailed deep-scan reporting features.
Offers broad multilingual AI detection and text humanization, but lacks GPTZero's detailed deep-scan reporting features.

SpecialistCombines AI detection with professional human proofreading and citation tools, but functions primarily as an editing service.
SpecialistCombines AI detection with professional human proofreading and citation tools, but functions primarily as an editing service.
SpecialistCombines AI detection with robust text humanization tools, but focuses more heavily on rewriting than pure verification.
SpecialistCombines AI detection with robust text humanization tools, but focuses more heavily on rewriting than pure verification.

Provides robust enterprise-grade content integrity and cross-media detection, but can be more expensive for individual users.
Provides robust enterprise-grade content integrity and cross-media detection, but can be more expensive for individual users.
Practise PTE Academic and PTE Core free, with AI scoring for speaking and writing
Practise PTE Academic and PTE Core free, with AI scoring for speaking and writing

Delivers strong fact-checking and comprehensive site-wide plagiarism audits, but has stricter paywalls than GPTZero.
Delivers strong fact-checking and comprehensive site-wide plagiarism audits, but has stricter paywalls than GPTZero.
Study smarter for IELTS, TOEIC and HSK with AI speaking and writing rooms
Study smarter for IELTS, TOEIC and HSK with AI speaking and writing rooms
AI English speaking coach with instant pronunciation feedback

Provides detailed sentence-level analysis for multilingual text, but lacks GPTZero's broad academic brand recognition.
Provides detailed sentence-level analysis for multilingual text, but lacks GPTZero's broad academic brand recognition.

PTE practice tests with instant AI scoring and realistic mock exams
PTE practice tests with instant AI scoring and realistic mock exams

Excels at scanning both text and images with high accuracy, but offers fewer free daily checks than GPTZero.
Excels at scanning both text and images with high accuracy, but offers fewer free daily checks than GPTZero.
AI detector that highlights evidence, not just a score
AI detector that highlights evidence, not just a score