IA Checker vs Undetectable AI: Which AI Detector Should You Use in 2026?

Positioning

Undetectable AI's detector page markets free checks with no signup, a 10,000-word UI limit, paraphrased AI detection, 50+ languages and strong accuracy claims citing independent tests and media reviews. Treat those figures as product messaging, not as a guarantee.

The brand's commercial centre of gravity is humanization. Pricing pages sell humanizer word quotas and list unlimited AI detecting on paid tiers. Detection and rewriting live in the same funnel.

IA Checker also includes Undetectable AI as a humanizer API option in the suite, and competes with it on the detector. This page compares the published detectors. We concede free volume and humanizer depth; we compete on multi-engine framing, EU hosting and compliance tooling.

Scorecard

Counted from the 22 rows in the table below, not asserted separately.

1. 7IA Checker ahead
2. 9Tied
3. 6Undetectable AI ahead

Feature comparison

Feature	IA Checker	Undetectable AI	Ahead
Accuracy
Detection engines	Multiple engines (Advanced and Ultra), with Pangram integration in progress	A free Undetectable AI detector trained on major model families, per its detector page (undetectable.ai)	IA Checker
Published accuracy marketing	Limits published beside the score; no universal accuracy percentage as the headline	Its detector page markets 99%+ accuracy and cites independent tests and media reviews (undetectable.ai)	Undetectable AI
Paraphrased or rewritten AI content	Multi-engine scores and sentence signals; paraphrased cases remain hard for every detector	Its FAQ states the tool is designed to identify rewritten or obfuscated AI content, including paraphraser output (undetectable.ai)	Undetectable AI
How a result is framed	An indicator, with limits published alongside the score	Marketing leans on high accuracy percentages; read claims as product messaging (undetectable.ai)	IA Checker
Models named as detectable	ChatGPT, Claude, Gemini and other current families	Its page names ChatGPT, GPT-5, Claude, Gemini, DeepSeek, Llama and more (undetectable.ai)	Tied
Coverage
Text detection	Yes	Yes	Tied
Image detection	Dedicated image detection route	An AI Image Detector is promoted across its detector and product surfaces (undetectable.ai)	Tied
Video detection	Dedicated video detection route	Not the focus of its published AI detector page (undetectable.ai)	IA Checker
Languages marketed for detection	Multi-language detection in the product workspace	Its FAQ markets 50+ languages, with English as the primary focus (undetectable.ai)	Undetectable AI
Humanizer product depth	Humanizer is part of the paid workspace; Undetectable AI is also available as an included API option	Humanization is the brand's core paid product, with detector access bundled on plans (undetectable.ai)	Undetectable AI
EU AI Act labelling	Built-in labelling tool with the official Article 50 disclosure icons	Not part of the published detector page (undetectable.ai)	IA Checker
Pricing
Free detector access	Free checks up to 20,000 characters	Free detector with no signup marketed; UI shows a 10,000-word limit (undetectable.ai)	Undetectable AI
Entry paid plan	€4.90 per month for 100,000 words, 25,000 characters per check	Humanizer plans from about $5 per month on annual billing, with unlimited AI detecting listed (undetectable.ai)	Tied
What you are mainly buying	Detection-led workspace with rewriting, plagiarism, translation and labelling	A humanizer-led product that also markets free and unlimited AI detecting (undetectable.ai)	Tied
Privacy
Detector retention messaging	Kept only for the duration of the requested operation unless you save it	Its detector FAQ states text is never stored or used to train models; read the full privacy notice for operative terms (undetectable.ai)	Tied
Hosting region	European Union	Privacy notice describes international transfers; EU-only hosting is not the published default (undetectable.ai)	IA Checker
Training on submissions	Not used for model training without express opt-in	Detector FAQ states submissions are not used to train models (undetectable.ai)	Tied
Workflow
Detection-to-rewrite loop	Detection plus humanizer, plagiarism, translation and grammar in one workspace	Detector and humanizer are the core funnel; pricing sells humanizer quotas with unlimited detecting (undetectable.ai)	Tied
Public API	No public API	Paid plans list API compatible among features (undetectable.ai)	Undetectable AI
File upload on the detector	Document upload flows in the product workspace	Detector UI markets paste or upload file (undetectable.ai)	Tied
Compliance
EU AI Act labelling	Built-in labelling tool with the official Article 50 disclosure icons	Not part of the published detector suite	IA Checker
GDPR posture	EU-established, GDPR-first	Privacy notice addresses EEA and UK rights; company is published as Undetectable LLC (undetectable.ai)	IA Checker

A free detector inside a humanizer brand

Undetectable AI's public story starts with making AI writing harder to flag. The free detector is both a useful checker and the on-ramp into humanization. If you already open that tab to rewrite, staying there for detection is the path of least friction.

IA Checker starts from the opposite end. Detection is the product entry, and rewriting is what follows when the score demands it. On iachecker.com the workspace is built so a single percentage is harder to over-trust: more than one engine, limits beside the score.

Neither shape is wrong. It depends whether you came for a rewrite quota or for a decision you may have to defend.

Accuracy headlines versus challenge-resistant scoring

Undetectable's detector page markets very high accuracy and cites independent tests and media roundups. That is strong positioning. It is still marketing about a probabilistic classifier, not a courtroom standard.

We do not lead with a universal accuracy percentage. We show multi-engine disagreement and print the limits next to the result. That will lose some headline comparisons and win some procurement conversations.

If you need a free second opinion on paraphrased drafts, try Undetectable's published detector. If the score has to survive challenge, start at iachecker.com and test both on the same samples.

Privacy defaults still matter after the FAQ

Undetectable's detector FAQ states text is never stored or used to train models. That is clear product messaging. The fuller privacy notice still describes account data, cookies and international transfers, so read the policy before pasting unpublished work.

We keep detector submissions only for the operation unless you save them, do not train without express opt-in, and process in the European Union. Those are stated product defaults rather than detector-page slogans alone.

For a quick blog check the difference may not matter. For candidate material or EU procurement, hosting region and retention usually matter before free word limits do.

IA Checker vs Undetectable AI FAQ

Is Undetectable AI's detector accurate?

Undetectable's detector page markets very high accuracy and cites independent tests and media reviews. No detector can honestly claim universal accuracy. On iachecker.com we take a different approach: more than one engine, disagreement made visible, and the limits printed next to the score. That will not win every benchmark headline, but it makes a single percentage harder to over-trust. Test both on your own writing.

Is Undetectable AI's detector free?

Yes, according to its detector page: free checks with no signup, and the UI shows a 10,000-word limit. Paid plans centre on humanizer word quotas and list unlimited AI detecting. IA Checker offers free checks up to 20,000 characters, then a detection-led paid workspace.

Can Undetectable AI detect paraphrased AI content?

Its FAQ states the detector is designed to identify rewritten or obfuscated AI content, including material modified by paraphrasing tools. That is product messaging worth testing. IA Checker does not claim paraphrased text is a solved problem; multi-engine disagreement is often the useful signal there.

Does Undetectable AI store text submitted to its detector?

Its detector FAQ says text is never stored or used to train models. Read the full Undetectable privacy notice for operative account, cookie and transfer terms. IA Checker keeps detector submissions only for the requested operation unless you save them, and processes in the European Union.

IA Checker vs Undetectable AI: which should I choose?

Choose Undetectable AI if you want a free no-signup detector and a humanizer-led product with unlimited AI detecting on paid plans. Choose IA Checker on iachecker.com for multi-engine detection, EU hosting, short retention and EU AI Act labelling when the score has to carry more weight.

Read next

• How AI humanizers work
• EU AI labels: the 3 official icons
• Try the AI detector
• All comparisons