AI Undetect does something few tools in its category do: its terms tie a credit refund to a measurable outcome. It also runs a genuinely multilingual site. Both matter when you shop for a replacement, and both are easy to miss. Here is what its own pages say, and where TextSight is and is not relevant.
Paste some text or load the example to estimate AI likelihood.
Most tools here either refuse refunds outright or offer a short no questions window. AI Undetect does neither. Its terms state "All purchases are non-refundable", then add: "A refund of credits is only available if a submission provably flags as less than 75% human on a reputable AI detector", with requests due "within 30 days of incident" (aiundetect.com/terms, checked 16 August 2026).
That is a conditional remedy with a number attached, denominated in credits rather than money, and it puts the burden of proof on you. How generous it is depends on what "reputable AI detector" means in practice, which the terms do not define. It is still more specific than most of this category.
Two other lines from the same document are worth reading before you commit to an annual plan: "The Company does not guarantee that your subscription will last for a full year or the specified subscription period", and if the company ceases operations, subscriptions terminate "immediately without any refund or compensation". Cancellation takes effect at the end of the current paid term. The operator names itself as "AIundetect LLC, doing business as AI Undetect"; no address is given in the terms.
From aiundetect.com/price, checked 16 August 2026:
| Plan | Monthly | Discounted rate | Words/month | Words per request | Detector |
|---|---|---|---|---|---|
| Basic | $15/mo | $5/mo | 10,000 on the discounted card, 15,000 on the monthly card | 500 | 30 times/day |
| Standard | $25/mo | $10/mo | 50,000 | 1,500 | Unlimited/day |
| Pro | $45/mo | $20/mo | Unlimited Words/Month | 3,000 | Unlimited/day |
A few observations, reported straight. The Basic monthly card lists 15,000 words while the discounted card for the same plan lists 10,000; we quote both rather than picking one. The page header advertises "60%off" while the Basic card is labelled "50%off". The Pro card carries the strapline "Best for light users", identical to Basic. Confirm your allowance in the account after purchase, not from the marketing page.
The free tier is stated clearly at signup: "After registration you will get 500 Free Rewrite Credits", with the editor capped at 250 words per input and ten detector uses, and Auto-Perfect mode reserved for paying accounts (aiundetect.com, checked 16 August 2026).
The site describes itself as "a freemium undetectable AI tool that helps you rewrite and reword AI-generated content to bypass AI detectors", names Turnitin, GPTZero, Copyleaks, ZeroGPT and Sapling as targets, and says plan output is "Undetectable by all AI Detectors" (aiundetect.com, checked 16 August 2026). It also states its model was trained on a "1B tokens corpus".
Those are AI Undetect's claims about AI Undetect. No public benchmark exists on which any of these tools have been jointly measured, so a claim on one vendor's page is not comparable with a claim on another's.
The homepage says "Supports 20+ languages worldwide" and its switcher lists English, Simplified and Traditional Chinese, Spanish, Portuguese, German, French, Japanese, Korean, Russian, Hindi, Arabic, Bengali, Italian, Dutch, Swedish, Danish, Norwegian, Finnish, Greek and Polish (aiundetect.com, checked 16 August 2026).
The localised site is served under path codes that are not the standard ISO forms: /es_SP, /pt_PO, /po_SH and /gr_EK all resolve and return content, where the conventional codes would be es, pt, pl and el. That is a technical observation about their URL scheme, not a comment on translation quality.
This matters for your shortlist. If you work outside English, AI Undetect covers ground that TextSight does not cover at all.
It sells evasion. We sell detection. If evasion is the outcome you are paying for, we do not replace it and you should compare AI Undetect against its direct competitors instead.
Keep it, or pick something like it, if:
We build the detector, and our rewriter is aimed at clarity rather than at moving a score. We publish no pass rate against anyone's system, because that is not the outcome we sell.
The people we suit are on the receiving end of text. Course leaders taking a first look at a submission. Publishers checking commissioned copy.
Be clear about our limits before you consider us. The detector is an English only ensemble of DeBERTa, RoBERTa and ELECTRA. It carries a known false positive bias against writers who learned English as a second language, which is exactly the population most likely to be harmed if a score is treated as proof. Given how much of AI Undetect's audience writes in Spanish, Portuguese, Arabic or Chinese, this is not a hypothetical mismatch. If that is you, we are the wrong tool twice over.
| Plan | Monthly | Annual (25% off) |
|---|---|---|
| Starter | $9.99 | $7.49/mo |
| Pro | $19.99 | $14.99/mo |
| Business | $39.99 | $29.99/mo |
| Enterprise | $79.99 | $59.99/mo |
The box above needs no account: 3 checks a day, pooled across the AI Detector and Document Detector, up to 1,000 words. A free account gives 60 checks a day at 5,000 words with history. Starter is 200 checks a day. Pro and above are unlimited. Minimum input is 25 words. Under 30 reads as likely human written, 30 to 69 as mixed signals, 70 and above as likely AI generated.
Sentence level analysis and PDF export begin at Starter. Chrome extension and REST API begin at Pro. Teams and branded reports begin at Business. File upload, URL scan and bulk scan are included.
We meter checks per day, not words per month. If your work is one long document a week, per day check counts will feel loose where a word pool would feel tight. If your work is hundreds of short snippets, the reverse.
Write down the sentence that describes what you want. If it contains "pass", "flag" or "score going down", you want a rewriting tool, and your shortlist is AI Undetect against its own category on per request caps, language coverage and refund terms.
If your sentence is closer to "I need to know what this reads as, and be able to show my working", run the paragraph you are worried about through the box above.
The deeper head-to-head: feature table, where GPTZero wins, where TextSight wins, and migration steps.
Read the comparePerplexity, burstiness, and transformer scoring explained, so you can read any detector's verdict critically.
Read the guideWhy detectors over-flag ESL and formal writing, and how sentence-level evidence helps you defend real work.
Read the guideThe full ranking with detection approach, pricing, and use-case fit side by side.
See the rankingStart with TextSight's free tier. No card, no signup, no commitment. Your first scan in about six seconds, with the evidence shown line by line.
Honest comparisons vs other tools.