// AI detectors
Copyleaks AI Detector
Multilingual AI and plagiarism detector with a generous no-login free scan.
official sources onlychecked 2026-10-26
01At a glance
| Official link | https://copyleaks.com/ai-content-detector |
|---|---|
| Made by | Copyleaks |
| Free? | Free scans up to 25,000 characters without logging in; a free account gives extra monthly credits (amount: check pricing). |
| Paid | Paid plans – see the pricing page. |
| Languages | AI detection in 30+ languages incl. English, French, German, Italian, Portuguese, Spanish, Japanese, Chinese (Simplified and Traditional) and more |
| Files | Paste text or upload (accepted file types: check the official page). |
| Limits | 25,000 characters per free scan without login. |
| Best for | Schools, businesses, multilingual content. |
02How to use it
- Open copyleaks.com/ai-content-detector.
- Paste up to 25,000 characters and scan – no login needed.
- Create a free account for more monthly credits.
03Accuracy
Official: over 99% accuracy and a 0.03% false-positive rate. Published per language (human / AI): English 99.97% / 99.20%, French 99.88% / 96.18%, German 99.94% / 95.63%, Italian 99.88% / 97.00%, Portuguese 99.95% / 93.08%, Spanish 99.85% / 98.02%.
Independent evaluations:
- Weber-Wulff et al. (2023), “Testing of detection tools for AI-generated text”, International Journal for Educational Integrity — 14 tools tested (12 public + Turnitin and PlagiarismCheck): all scored below 80% accuracy and only 5 above 70%; the authors conclude the tools are “neither accurate nor reliable”. False positives ranged from 0% (Turnitin) to 50% (GPTZero) on their test set; machine paraphrasing cut accuracy to 26%. English texts, tested in 2023 – tools have changed since.
- Liang et al. (2023), “GPT detectors are biased against non-native English writers”, Patterns — Several widely used GPT detectors “consistently misclassify non-native English writing samples as AI-generated, whereas native writing samples are accurately identified”; simple prompting can also bypass them. The authors caution against using detectors in evaluative or educational settings.
04FAQ
FAQ
Can Copyleaks detect Chinese AI text?
Yes – Chinese (Simplified and Traditional) is in its supported list; per-language accuracy is published only for some languages (Chinese not among them).
Can Copyleaks AI Detector be wrong?
Yes – AI detection can misjudge. These are the vendor’s own figures; independent studies have found lower accuracy for detectors in general. AI detection may misjudge.
05Official sources
Checked against these pages on 2026-10-26; the official page wins if anything differs.