How does the plagiarism and AI checker work?
Updated August 6, 2026
Paste or upload your work and it runs two scans, an AI-writing estimate and a match against published sources. Free covers 1,000 words in total, Pro 25,000 a month.
What the checker scans
Both checks run on the same text. You do not choose between them.
- AI Detection estimates how much of the text reads as AI writing. You get one figure, a High, Medium or Low confidence rating, and passage by passage highlights.
- Key Sentences pulls out the passages that scored most AI and most human.
- Common AI Phrases counts the stock wording it found, such as "delve" or "in today's fast-paced world". View Details lists them.
- Plagiarism Detection compares your text against published web pages and academic sources. Matched Phrases links each match to its source, so you can check whether it needs a citation or a rewrite.
- Choose Paste Text or Upload File. You can upload one PDF, TXT, DOC or DOCX file, up to 50 MB.
- Give it at least 75 words. Shorter text is refused.
- Select Scan text and wait on the page.
If your account is linked to a school, the checker opens only when the school turns it on. Teacher accounts do not get this page and use the checker inside a classroom instead.
Open the checkerWhat the AI result means
The AI score comes from an AI detection provider. It describes how the writing reads to that detector, not how the text was written. It is not a mark.
Read the confidence rating before the score. Low confidence is weak evidence either way. A high score tells you a passage reads the way AI writing tends to read, which is a reason to rewrite it in your own voice, not a finding that you did anything.
To decide what to rework, use the highlights and the Key Sentences list, not the headline number.
How many words you get
- Free: 1,000 checker words in total, one time only. One scan can use up to 1,000 words, or whatever is left of the 1,000.
- Pro: 25,000 checker words a month. One scan can use up to 5,000 words.
Pro words reset on your own renewal date, not on the 1st of the month. On Pro the checker page shows Monthly usage and a Next reset in countdown.
If your text is longer than the per-scan limit, the checker reads the first words up to that limit and tells you how many it used. A full IA or EE will not fit in one scan on Free, so scan it in sections, starting with the ones that matter most.
The coursework grader shares this allowance. Ticking Run AI-writing and exemplar similarity checks when you submit coursework spends the same words.
What happens to your text
Your text is not added to any plagiarism database, so scanning here does not cause a later Turnitin check to flag your own work back at you. It is not used to train AI models.
Finished scans stay in Scan History, so you can reopen them. To delete one, open it, choose More, then Delete. Deleting a scan cannot be undone.
The checker is web only. The phone app shows a link that opens the web version in a browser.
