Plagiarism detection tools can identify when you have changed the wording of a passage. Modern plagiarism checkers use semantic analysis to find similarities in meaning between pieces of text rather than only matching actual words, then flagging any text that is similar to text from their databases even if the wording was changed. Basic plagiarism checkers usually only compare exact words and therefore do not detect most paraphrased material. More sophisticated tools, including Quetext's Plagiarism Checker, use deep search algorithms and contextual analysis to catch synonymized or restructured sentences that preserve the original meaning, scanning for both direct matches and paraphrased content in a single pass.

No paraphrasing checker is completely reliable in detecting or verifying corrections, and even if extensive rewrites are made, you should continue to use citations as usual to show your purpose. So, to learn more about the features of these devices in greater depth and see how they operate behind-the-scenes, this 2026 guide to AI plagiarism checkers walks through it.