iLang Detect and GPTZero both aim to detect AI written text, but they take different approaches. iLang is completely free with no signup, scanning texts sentence by sentence across six dimensions and giving you fix suggestions for each problem. GPTZero is a freemium tool built for educators, offering document level probability scores with sentence highlighting and a suite of features like plagiarism checking and authorship replay.
So which one should you use? That depends on what you need. If you want to improve your writing and fix the issues, iLang gives you a path forward. If you need to prove authorship or batch scan documents for a classroom, GPTZero has the institutional tools. Neither is perfect, but one is free and the other is well established.
Side by side
scroll sideways on small screens →| Feature | iLang Detect | GPTZero |
|---|---|---|
| Pricing | Free | Freemium; Premium from US$12.99/mo (annual billing, per gptzero.me; live pricing page geolocates currency) |
| Free tier | Free to use, no signup | Free plan: 10,000 words/month scanned (no credit card), incl. Chrome extension; free accounts can scan texts up to 150,000 characters or batches up to 250 files (per gptzero.me/students and gptzero.me/faq) |
| Output style | Sentence-level issue list across 6 dimensions (vocabulary, structure, tone, punctuation, logic, rhythm) plus an AI probability score | Document-level AI probability with sentence-level highlighting |
| Languages | English (Chinese version at detect.ilang.cn) | Multilingual: "support for English, Spanish, French, German, and other languages" (gptzero.me/faq); 'Multilingual AI detection' is a Premium-plan feature |
| Fix suggestions | Yes: every flagged fragment gets a problem explanation and a fix suggestion, plus overall rewrite advice | Not advertised; detection only |
| API | Not public yet | Yes |
| Best for | Writers and editors who want to fix the text, not just get a score | Educators and students first ("Trusted by over 10 million teachers and students", official AI-detector partner of the American Federation of Teachers), plus writers and recruiters |
| Vendor accuracy claim | No accuracy percentage claimed. iLang shows the markers themselves, so you can judge every flag instead of trusting a number. | "when the confidence_category field is high, 99.1% of human articles are classified as human, and 98.4% of AI articles are classified as AI" , gptzero.me (no single overall accuracy percentage stated) |
Where they differ
Pricing and Access
iLang is completely free with no signup or rate limits. You can use it as much as you want. GPTZero offers a free plan that limits you to 10,000 words per month, and its premium plans start at $12.99 per month. The free plan also requires a signup. For someone who just wants to check a few paragraphs, iLang is the easier option. But for educators who need to scan many documents, GPTZero's paid plans offer batch scanning and LMS integration.
Output and Guidance
iLang gives you a sentence level issue list across six dimensions: vocabulary, structure, tone, punctuation, logic, and rhythm. Each flagged fragment includes a problem explanation and a fix suggestion. GPTZero provides a document level probability score with sentence highlighting, but no direct suggestions for improving the text. It tells you if a sentence looks AI generated, but not how to change it. If you want to revise your writing, iLang guides you. If you only need a score, GPTZero gives you that.
Target Audience
GPTZero was built for educators and students. It is trusted by millions of teachers and integrates with learning management systems. It also offers plagiarism checking and authorship replay to prove human writing. iLang is designed for writers and editors who want to fix their text, not just get a score. It focuses on helping you improve the writing itself. So if you are a teacher grading papers, GPTZero fits. If you are a writer polishing a draft, iLang is the better tool.
Which one to pick
Choose GPTZero for institutional detection needs.
If you are an educator, recruiter, or anyone who needs to prove authorship or batch scan large volumes of text, GPTZero is the right tool. Its free plan covers 10,000 words a month, and paid plans add multilingual detection, plagiarism checking, and API access. It is the standard in schools.
Choose iLang for free, actionable editing suggestions.
Writers and editors who want to fix AI sounding text will love iLang. It identifies issues across six dimensions and gives you specific suggestions for each problem. No signup, no cost, no limits. You can paste your draft and get a rewrite guide in seconds. Perfect for content creators and students who want to improve their writing.
Use both to detect and then fix AI text.
Run your text through GPTZero to see if it flags any AI content. Then paste the flagged sentences into iLang to get specific fix suggestions. GPTZero tells you what to look at, iLang tells you how to change it. This combination gives you both detection and correction in one workflow.
Frequently asked questions
Yes, iLang is completely free to use with no signup required. There are no rate limits, so you can scan as much text as you want. GPTZero's free plan limits you to 10,000 words per month.
Accuracy depends on the text and the AI model used. GPTZero claims high accuracy when confidence is high, but has known false positives, like flagging the US Constitution as AI. iLang focuses on identifying specific writing issues rather than giving a single accuracy percentage.
Yes, GPTZero's Premium plan includes multilingual detection for English, Spanish, French, German, and other languages. iLang currently supports English, with a Chinese version available at detect.ilang.cn.
iLang requires no signup at all. GPTZero's free plan requires a signup and limits you to 10,000 words per month. Paid plans start at $12.99 per month and offer more features.
See the issues, not just the score
Paste the same draft you ran through GPTZero. Free, no signup, nothing stored.