Disclaimer
Last updated: 18 February 2025
Accuracy of results
PenProof uses heuristic analysis to estimate the likelihood that text was generated by AI. No AI detection tool is 100% accurate. Our scores represent a probabilistic estimate, not a definitive verdict. Results should not be used as the sole basis for academic, legal, or employment decisions.
What our scores mean
- • 0–34 (Human): Strong human authorship signals detected. Low probability of AI generation.
- • 35–64 (Uncertain): Mixed signals. The text may be human-written, AI-assisted, or human-edited AI output.
- • 65–100 (AI): Strong AI generation patterns detected. High probability of AI authorship.
These thresholds are calibrated against known AI and human text samples, but edge cases exist. Skilled human writers may occasionally trigger AI patterns, and polished AI text may score low.
Known limitations
- • Short texts (under 150 words) produce less reliable results.
- • Translated text, highly technical writing, and formulaic content (legal, medical) may produce elevated AI scores.
- • AI text that has been extensively human-edited may score lower than expected.
- • Our heuristics are optimised for English. Other languages may produce less accurate results.
No guarantee
THE SERVICE IS PROVIDED "AS IS" WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED. WE DO NOT GUARANTEE THE ACCURACY, COMPLETENESS, OR RELIABILITY OF ANY ANALYSIS RESULTS. USE AT YOUR OWN DISCRETION.
Intended use
PenProof is designed as an informational tool for readers who want an additional signal when evaluating online content. It is not a plagiarism detector, and it is not designed for use in academic integrity enforcement, hiring decisions, or legal proceedings.