Phrasly vs Undetectable AI

Undetectable AI's trial is free and small: 250 words once, checked on 8 November 2026, which is one long paragraph. Phrasly's free allowance is one humanization a day of up to 500 words with no sign-up, stated on its humanizer page, read 9 November 2026. Its trial costs $2.00 and a card for three days, with 1,000 humanization words and an 800-word cap per process, read 9 November 2026, and the vendor states it can be upgraded early at any time.

Undetectable AI trial checked on 8 November 2026; Phrasly trial read 9 November 2026. For a reader who wants to see what each tool does to a paragraph, both will show it, one for nothing. For a reader who wants to see what each tool does to a full essay section before paying for a year, only Phrasly's trial reaches that length, and it costs $2.00. Neither trial converts into a subscription on its own.

Undetectable AI sells words a month, 10,000 on the entry plan, on a slider with the yearly toggle on by default, read 9 November 2026; 10,000 words is about six 1,500-word essays or twenty 500-word sections. Phrasly sells one plan with no stated monthly cap and a 5,000-word cap per process, read 9 November 2026, so the month is not the limit; the piece is. Price is reported on this site and never scored.

Undetectable AI figures read 9 November 2026; Phrasly figures read 9 November 2026. Under 10,000 words a month, Undetectable AI's $60.00 a year is the smaller charge by $71.88, and its $9.99 month-to-month option is the only one of the two that does not ask for a year. Past 10,000 words, Undetectable AI's price climbs the slider and Phrasly's does not move. On request size the two also differ in kind: Phrasly prints a cap, 5,000 words, and Undetectable AI prints none, which means Undetectable AI's long-document behaviour is whatever its interface does on the day, and the published method records that in the raw files rather than from the page.

Phrasly's guarantee terms name three modes for Phrasly Ultra, Balanced, Strong and Max, read on its pricing page on 9 November 2026, which implies a ladder from a lighter rewrite to a heavier one; the page does not describe what each changes. Undetectable AI names no modes on its pricing page, read the same day. For a reader who wants the lightest rewrite that still changes how a text reads, only one of these two offers a named bottom rung.

The method runs each tool on its default setting and on its strongest documented mode as a second row. For Phrasly that means two rows, with the default recorded from the interface on the run date; for Undetectable AI the run uses whatever the interface shows and records the name.

No peer-reviewed study has tested either product by name in a way this site could cite, so the research here is about the category. Weber-Wulff and colleagues tested 14 detectors and found every one below 80 percent accuracy, with accuracy falling further on paraphrased and machine-translated text (Weber-Wulff et al. 2023, International Journal for Educational Integrity, read 9 November 2026). GPTZero, one of the five detectors in the site's panel, states that its model shields against common evasion methods including paraphrasing and keeps its false positive rate at no more than 1 percent when evaluating AI against human text (GPTZero technology page, read 9 November 2026).

Phrasly makes two claims of its own. Its pricing page states an average human score of 99.7 percent across the vendor's own testing of more than 100,000 documents, read 9 November 2026, on inputs the vendor chose and with no method on the page. Its guarantee refunds the latest payment if any public humanizer's output scores more human than a Phrasly Ultra draft of the same 500-plus words on Pangram, GPTZero, Copyleaks and Originality.ai, with claims due within 14 days, read 9 November 2026. Three of those four detectors sit in this site's panel, so a reader can line the claim up against a dated run once one is published; until then the claim stands as a claim. Undetectable AI's pricing page makes no detector claim at all, which is the more modest position and no evidence either way.

Those sources measure detector readings, not whether the rewritten text kept the writer's claims. The method on this site weights meaning kept at 35 points of 100, errors introduced at 20, detector pass rate at 30 and limits and access at 15, and two editors rate every output blind. When a run is published, this page gains meaning, error and per-detector fields for both tools. No detector score should be the only evidence in a misconduct case.