About Copyleast
Clear checks need clear limits.
Copyleast helps students review plagiarism matches and probabilistic AI signals without confusing the two or treating one score as a final verdict.
Why Copyleast exists
Checking should explain the result, not oversimplify it.
Plagiarism checking and AI detection answer different questions. One looks for similarity to available sources. The other estimates whether writing patterns resemble AI-generated text.
Copyleast keeps those results separate and gives users enough report context to review them carefully. The service identifies signals that deserve attention; it does not decide who wrote a document or whether misconduct occurred.
How we approach checking
Four principles behind Copyleast.
Keep plagiarism and AI separate
Source similarity and AI-associated writing patterns have different meanings. Copyleast does not combine them into one misleading score.
Show what sits behind the result
A report may include highlighted passages, available source links, per-source similarity, AI probability, Total AI rate and sentence-level indicators.
Explain what the tools cannot prove
A similarity match does not automatically prove plagiarism. An AI result cannot prove authorship or reliably identify a specific AI model.
Give users control over their documents
Submitted documents are not used to train AI models or automatically added to the general comparison database. Users can delete documents and their accounts.
Copyleast in numbers
The scale behind the checking service.
These figures describe the service and its supported checking environment. They do not represent a guaranteed accuracy rate.
- 10+
- years of checking experience
- 70+
- supported languages
- 300M+
- texts checked
- Billions
- of web pages available for comparison
- Thousands
- of academic publications
- 24 MB
- per file, with up to 10 files in one check
How trust is built
Trust starts with what the report does—and does not—say.
Copyleast reports source similarity and probabilistic AI indicators in separate views. That separation reduces the risk of treating unrelated metrics as one conclusion.
The report can support a careful review, but it does not replace citations, drafts, writing history, assignment rules or human judgment.
Privacy controls are part of the same approach: documents are not used for model training, private repositories require explicit activation, and users can remove their own material.
What Copyleast does not claim
Three limits we state clearly.
One score tells the whole story
A percentage summarises part of a report. It cannot explain every quotation, citation, common phrase, draft or writing decision.
AI detection proves authorship
AI detection is probabilistic. It can produce false positives and false negatives, and it cannot reliably establish who wrote a document.
A detected model name is certain
Copyleast does not claim to identify ChatGPT, Claude, Gemini or another specific model reliably from the finished text.
