// AI Apps · Topic
AI detectors (AI checkers)
Official links, free limits, languages and file types for 6 tools. AI detection can misjudge – read the results as hints, not proof.
6 toolsofficial sources onlychecked 2026-10-26
01AI detector comparison
| Tool | Free? | Languages | Files |
|---|---|---|---|
| GPTZerogptzero.me | Free to start; scans over 10,000 characters need a free account. Free monthly allowance: check the official pricing page. | Officially “fully supports” English, German, Portuguese, French and Spanish. | Paste text or upload a file (accepted file types: check the official page). |
| Turnitin AI writing detectionwww.turnitin.com | Not free and not sold to individuals – access is through your institution’s licence. | English; Spanish (since Sept 2024); Japanese (since April 2025). | Submissions through the institution’s Turnitin workflow (file types per Turnitin’s submission rules). |
| Originality.aioriginality.ai | Free plan: 10K words one time (100 credits); 1 credit = 100 words. | Check the official page. | docx, doc, pdf upload, or paste text. |
| Copyleaks AI Detectorcopyleaks.com | Free scans up to 25,000 characters without logging in; a free account gives extra monthly credits (amount: check pricing). | AI detection in 30+ languages incl. English, French, German, Italian, Portuguese, Spanish, Japanese, Chinese (Simplified and Traditional) and more | Paste text or upload (accepted file types: check the official page). |
| Tencent Zhuque AI Detectormatrix.tencent.com | Free. Guests: 3 text + 3 image checks per day. Logged in: 20 text + 30 image/video checks per day; feedback (like/dislike) adds 5 more, up to 30 bonus. | Chinese and English (benchmarks published for both). | Text: txt, docx; images: png, jpg, webp; video: mp4, mov, avi. |
| CNKI AIGC checkcx.cnki.net | Paid per check (price shown after login – check the official page). | Chinese (aimed at Chinese academic writing); others: check the official page. | Check the official page. |
02Accuracy: what each vendor says
Official claim: 99.9% accuracy; false-positive rate for ESL writing reduced to 1%.
In the 2023 Weber-Wulff et al. study (tested in 2023), GPTZero had the highest false-positive rate of the tools tested. Vendors’ own figures are not independent evaluations.
Turnitin publishes no single accuracy number on the guide we checked. In Weber-Wulff et al. (2023) Turnitin had 0% false positives in that test set, but all tools scored below 80% accuracy overall.
Turnitin: the AI score “should not be used as the sole basis for adverse actions against a student”.
Official claim: “the Most Accurate AI Detector in third-party studies” (vendor statement).
Vendor claims are not independent evaluations; AI detection may misjudge.
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%.
These are the vendor’s own figures; independent studies have found lower accuracy for detectors in general. AI detection may misjudge.
Official: overall text accuracy above 92%; image accuracy 98%+. Official benchmark table (data updated 2026-06-30): HC3 Chinese 99.00%, Detect-RL Chinese 98%, AIGTBENCH 96.9%, MAGE 97.72%, RAID TPR@FPR=5% 99.95%, HC3-en 100%, M4GT 100%. Model updated 2026-07-21.
Tencent itself says Zhuque “is not 100% accurate and can have false positives” – e.g. web novels and elementary-school essays written in simple, generic language – and results should be treated as reference only.
No official accuracy figure found on the public page.
AI detection may misjudge; follow your school’s rules on how AIGC results are used.
03What independent studies found
- 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
Which AI detector is the most accurate?
There is no independent, up-to-date ranking we can cite. Every vendor publishes its own high numbers, while the 2023 Weber-Wulff et al. study found all 14 tools it tested below 80% accuracy. Use detectors as one signal, not a verdict.
Is there a free AI checker?
Yes: Zhuque (Tencent) is free with daily limits; Copyleaks scans up to 25,000 characters free without login; GPTZero is free to start (account needed over 10,000 characters); Originality.ai gives 10K words once. Turnitin and CNKI are not free for individuals.
Can AI detection be wrong?
Yes. AI detection can misjudge. Tencent says Zhuque “can have false positives”, Turnitin says its score should not be the sole basis for action, and Liang et al. (2023) found detectors flag non-native English writing as AI far more often.
Which AI detector works for Chinese?
Zhuque publishes Chinese benchmarks and CNKI AIGC check targets Chinese academic writing; Copyleaks lists Simplified and Traditional Chinese. GPTZero’s fully supported languages do not include Chinese.
Is 朱雀ai检测 free?
Yes – 3 text + 3 image checks a day as a guest, 20 text + 30 image/video a day when logged in.