Free · Writing · 3 of 5 tools · updated Oct 17, 2026
Free AI tools for AI content detection
QuillBot is the strongest tool for AI content detection you can use without paying, at 11/100. What you get for nothing: Premium from $4.17/mo billed annually. 3 of the 5 tools tracked for this job have a free tier, an open-source licence, or are free outright. It is also the top-ranked tool for this job overall, free or not.
Same evidence score as the ranking — GitHub stars, Hacker News mentions, release activity, free access — recomputed nightly, never sold. See all 5 tools for AI content detection.
Top 3
evidence / 100
+ The paraphraser's mode slider (fluency, formal, simple, creative) is the fastest way to rework a clumsy paragraph.
− Paraphrased text sometimes changes meaning, and its humanizer and detector are unreliable against serious detection tools.
+ Supports 30+ languages and integrates with Canvas, Moodle and Blackboard.
− Credit-based pricing is confusing, and false positives on edited human text are common.
+ Highlights which sentences look AI-generated and offers a Google Docs writing replay as supporting evidence.
− Like all detectors it produces false positives, particularly on non-native English writers.
All 3, side by side
| Tool | Score | Pricing | What you get free | Platforms |
|---|---|---|---|---|
| QuillBot | 11 | Free tier | Premium from $4.17/mo billed annually | web, mac, windows, ios, android, chrome-extension |
| Copyleaks | 10 | Free tier | AI Detector from $7.99/mo | web, api, chrome-extension |
| GPTZero | 10 | Free tier | Essential from $8.33/mo billed annually | web, chrome-extension, api |
A free tier counts, and so does an open-source licence you can self-host — both are in the table, so a tool that is only free for a trial is not here.
Head to head: QuillBot vs Copyleaks