AI detectors all claim to spot machine-written text, but they don't all help you do something about it. iLang Detect is completely free, requires no signup, and goes beyond a simple score. It highlights sentence-level issues across six dimensions and gives you a fix suggestion for each one. Undetectable AI also offers a free detector with no signup, but its main draw is a paid Humanizer that rewrites flagged text. Which tool actually helps you become a better writer?
Side by side
scroll sideways on small screens →| Feature | iLang Detect | Undetectable.ai AI Detector |
|---|---|---|
| Pricing | Free | Freemium; paid from $5.00/mo billed yearly ($60/yr; $9.99 monthly), mainly for Humanizer credits, with unlimited AI detection included |
| Free tier | Free to use, no signup | Detector is free with no signup and instant results; the paid Humanizer's free trial caps at 250 words. |
| Output style | Sentence-level issue list across 6 dimensions (vocabulary, structure, tone, punctuation, logic, rhythm) plus an AI probability score | Aggregated verdicts across multiple detector models |
| Languages | English (Chinese version at detect.ilang.cn) | 50+ languages claimed, English first (vendor statement). |
| Fix suggestions | Yes: every flagged fragment gets a problem explanation and a fix suggestion, plus overall rewrite advice | No fixes; sells a separate AI Humanizer |
| API | Not public yet | Yes (undetectable.ai/develop; paid plans marked API compatible) |
| Best for | Writers and editors who want to fix the text, not just get a score | Bloggers, SEO and content writers, students and freelancers; in practice, people who detect first and then humanize |
| Vendor accuracy claim | No accuracy percentage claimed. iLang shows the markers themselves, so you can judge every flag instead of trusting a number. | Vendor claims "100% detection, 0% false positives" and cites peer-reviewed research of "up to 100% accuracy" (undetectable.ai/ai-detector). |
Where they differ
Output: fixes vs. scores
iLang Detect shows you exactly which sentences look AI-generated and explains why: vocabulary, structure, tone, punctuation, logic, or rhythm. Every flagged fragment comes with a problem explanation and a fix suggestion, plus overall rewrite advice. Undetectable AI gives you aggregated verdicts across multiple detector models (ChatGPT, GPT 5, Claude, Gemini, etc.) but offers no text-level fixes. If you want to improve your writing, not just get a score, iLang gives you a path forward.
Pricing and conflict of interest
iLang is completely free with no signup and no rate limit. You can use it as much as you want. Undetectable AI's detector is free, but the company also sells a Humanizer that rewrites text to evade detection. That's a clear conflict of interest: they detect AI and then help you hide it. Paid plans start at $5 per month billed yearly. Independent reviews on Trustpilot and sites like Originality.ai show inconsistent results, and some users report billing issues after cancellation.
Accuracy claims and reality
Undetectable AI claims "100% detection, 0% false positives" and cites peer-reviewed research of "up to 100% accuracy." Independent tests paint a different picture: bypass results swing from 0% to 93% depending on the tester, and Originality.ai found that the Humanizer's output was still 100% AI flagged. iLang doesn't make overblown accuracy promises. It gives you a transparent set of flagged sentences with explanations, so you can decide what to change.
Which one to pick
Choose this if you need a quick detection + humanization pipeline.
If your main goal is to get a score and then rewrite text to avoid detection, Undetectable AI bundles both steps. Its free detector gives you a verdict from multiple models, and the paid Humanizer can rewrite text in one click. This works well for SEO content or bulk posts where speed matters more than understanding the changes.
Choose this if you want to learn and fix AI issues yourself.
iLang is perfect for writers, editors, and students who want to improve their actual writing. It shows you exactly which sentences are problematic and why, then gives you a fix suggestion for each one. No signup, no limits, no conflict of interest. You retain full control over your edits.
Use both when you want wide detection plus final polish.
Run your text through Undetectable AI first to get a quick multi-model verdict and a humanized version. Then paste that humanized version into iLang to catch any remaining rhythm or logic issues. iLang's fix suggestions will help you refine the final draft so it sounds natural, not just evasive.
Frequently asked questions
Yes, iLang Detect is completely free. You don't need to create an account or log in. There's also no rate limit, so you can use it as much as you want. It's designed to be a straightforward tool for anyone who wants to check and improve their writing.
Undetectable AI claims support for 50+ languages, but English is its primary focus. Independent tests mostly cover English. iLang currently supports English and has a Chinese version at detect.ilang.cn. If you primarily write in English, both tools work well, but iLang's Chinese support is a plus for bilingual users.
Absolutely. Undetectable AI gives you a verdict but no specific fixes. iLang can take that same text and show you which sentences are flagged across six dimensions, with a problem explanation and a fix suggestion for each. It's a great complement if you want to understand and improve the flagged parts yourself.
Undetectable AI claims 100% accuracy, but independent tests show inconsistent results, with bypass rates varying from 0% to 93%. iLang doesn't claim a single accuracy number. Instead, it gives you a transparent breakdown of sentence-level issues along with probability scores. Both tools have their strengths, but iLang's honesty about limitations is a plus for critical users.
See the issues, not just the score
Paste the same draft you ran through Undetectable AI. Free, no signup, nothing stored.