AI detector free tiers, compared

Field sorted: free words per month on each card, from the vendor's pricing or plans page read on 8 November 2026. Direction: more ranks higher. Tie rule: none needed; a tie would break on the larger limit per check, then product name. Qualification rule: the vendor must state a free allowance in words per month; a per-check, per-day or one-time allowance becomes monthly only by assuming how often a reader scans, and the index never derives a number the vendor did not publish, so those 68 cards sit in the second table (none of the nine eleventh-wave cards states a monthly word figure). 4 of 72 qualified, AI or Not from 9 November 2026, and none of the ten fourth-wave cards states a monthly word figure (Smodin, Surfer and Deepware state free use with no quantity, Quetext 1,000 words per scan, BrandWell 2,500 or 10,000 characters per check, TruthScan 25 results a month counted in images and PDF pages, Sightengine 2,000 operations a month, Compilatio and Sensity no free detector, DetectGPT free code with no hosted checker); Turnitin qualifies at 0 because the vendor states no free access exists. Full rules: methodology page; no record in the studies index measures free tiers.

The free checks per day ranking, added 9 November 2026, sorts the other unit vendors use: Sightengine, SynthID, Pangram and QuillBot state a daily figure in checks rather than a monthly one in words, and the free API question lists the ten free allowances that reach an API.

Vendors use different units on different pages. ZeroGPT states words per month in a compare table but characters per detection in the plan card (zerogpt.com/pricing). GPTZero states 10,000 words per month in a blog post dated 25 October 2026 and 10,000 characters per scan in the FAQ (gptzero.me, gptzero.me/faq). All read 8 November 2026; the Updated line is the date each figure was last seen.

A free tier and a check without an account are different fields: 15 cards state that a check runs with no sign-up or login, on the no-account view, added 9 November 2026, and the account-less route is usually the smallest, GPTZero's 10,000 characters against 150,000 with a free account.

Four of the tiers in this ranking's second table are sold under a student or academic name, Isgen Academic, Compilatio Studium, Detecting-AI.com Scholar and ZeroGPT EDU, and the student plan question lists them with their prices beside the nine cards that sell education to institutions only, read 10 November 2026.