IsItAI vs ZeroGPT: AI detector comparison
A side by side look at pricing, methodology, language support and best-fit use case. Every claim on this page is linked to a source at the bottom.
Last updated . Reviewed by IsItAI Editorial.
At a glance
IsItAI
UK, 2024UK-built AI detection that gives you a confidence score, not a verdict.
- Pricing
- From £4.99/month
- Free tier
- 5 scans/day free
- API
- Yes
- Languages
- 30
ZeroGPT
France, 2023Free, fast, ad-supported detector popular with students.
- Pricing
- From $9.99/month (ad-free)
- Free tier
- Unlimited free (with ads)
- API
- Yes
- Languages
- 50
Side by side
| Feature | IsItAI | ZeroGPT |
|---|---|---|
| Free tier | 5 scans/day free | Unlimited free (with ads) |
| Starting price | From £4.99/month | From $9.99/month (ad-free) |
| Cost per 1k words | £0.05 (Pro plan equivalent) | Free |
| API available | Yes | Yes |
| Languages supported | 30 | 50 |
| Founded | 2024 | 2023 |
| Country | UK | France |
| Primary audience | Educators, recruiters and content teams | Students and casual users |
| Best for | Teachers, students and recruiters who want a clear confidence score and source-passage highlighting | Casual one-off checks where price is the main constraint |
| Known weakness | Smaller brand than US incumbents | Inconsistent results have been reported across runs on identical input |
How each tool works
IsItAI
Method: Multi-model ensemble. Combines several open detectors and weights agreement. Returns a confidence band rather than a binary verdict.
Data handling: GDPR compliant. UK and EU hosted. Submitted text is not stored after the scan completes.
ZeroGPT
Method: Web-based classifier. Free tier funded by display advertising.
Data handling: Stores submissions. Public retention policy is limited.
How accurate are AI detectors? What the research says
Two findings from independent academic research apply to almost every detector on this list, including IsItAI and ZeroGPT.
1. False positives on non-native English writers. Liang et al. (Stanford, 2023) found that GPT detectors flagged over half of TOEFL essays written by non-native English speakers as AI-generated, while flagging almost none of the essays from US students. If your use case involves non-native English writers, never treat a detector verdict as proof on its own.
2. Paraphrasing reliably defeats classifiers. Sadasivan et al. (Maryland, 2023) showed that running AI output through a paraphraser drops detection performance close to chance. Both IsItAI and ZeroGPT are vulnerable to this.
Where IsItAI wins
- Consistent results on identical input. Independent reviewers including Tooltester have flagged ZeroGPT's run-to-run variance.
- No display advertising on the result page, which is important when scanning student or candidate work.
- GDPR compliant UK hosting with no submission retention. ZeroGPT's retention policy is unclear.
Where ZeroGPT wins
- Free unlimited checks for casual users who can tolerate the ad-supported interface.
- Multilingual coverage at 50 claimed languages.
- No login required for one-off checks.
Which one should you pick, IsItAI or ZeroGPT?
Pick IsItAI for any decision that has consequences (a grade, a hiring call, a publishing decision). Pick ZeroGPT only for low-stakes curiosity checks where the ads do not matter. Reliability and data handling are the deciding factors here, not price.
Frequently asked questions
Is IsItAI free?
5 scans/day free
Is ZeroGPT free?
Unlimited free (with ads)
Can either tool be fooled by paraphrasing?
Yes. Sadasivan et al. (2023) demonstrated that paraphrasing reliably defeats most AI classifiers. Treat any detector verdict as a screening signal, not proof.
Are AI detectors fair to non-native English writers?
Independent research (Liang et al. 2023) found high false-positive rates for non-native English writing. Always combine a detector signal with other evidence, never use it as a sole basis for an academic or hiring decision.
Which one should I pick if I have to choose one, IsItAI or ZeroGPT?
Pick IsItAI for any decision that has consequences (a grade, a hiring call, a publishing decision). Pick ZeroGPT only for low-stakes curiosity checks where the ads do not matter. Reliability and data handling are the deciding factors here, not price.
Try IsItAI free
5 free scans a day. No credit card. UK hosted and GDPR compliant.
Sources and further reading
- IsItAI homepage
- Pricing
- How it works
- ZeroGPT homepage
- Tooltester independent comparison covering ZeroGPT
- Liang et al. (Stanford, 2023): GPT detectors are biased against non-native English writers
- Sadasivan et al. (2023): Can AI-generated text be reliably detected?