DetectGPT

DetectGPT, made by CoreAI LLC, is a free AI writing checker at detectgpt.io that scores a piece of prose on how much it still sounds like language-model output. It serves students, teachers, writers and anyone who used a model and wants a look at a draft before someone else does.

A user pastes a draft of up to 5,000 words, or a public page URL, and DetectGPT reads only the finished text rather than opening a ChatGPT, Claude, Grok or Gemini account or seeing the original prompt. It scores habits such as even sentence length, generic transitions, and safe wording, then returns a percentage plus yellow, orange and red highlighted lines showing which passages still sound machine-made.

A separate Plagiarism Checker tab runs a similarity score against public web pages, listing source links next to matching phrases, up to 5,000 words. DetectGPT does not rewrite a flagged draft itself; a user rephrases the stiff lines and can rescan to see the percentage move. Checks run entirely without an account or school login, and a result link can be shared instead of re-pasting a draft.

DetectGPT is free, with no account, card or daily cap, limited to 5,000 words per run and strongest on English text. It cannot prove who wrote a sentence, cannot match a school's private Turnitin report, and cannot scan images, slides or scanned PDFs; login walls and app pages also cannot be analyzed by URL. Text pasted into the checker is scored in the browser, and history stays on that device.

Use cases

• A private pass over a paper before handing it in
• Catching generic phrasing before a client or editor does
• Checking prose from a second-language writer for false alarms
• Running a similarity check on a draft against public pages