How does a plagiarism detector work: check your text for originality

Authors of articles, theses, plagiarism free essays, reports, and research papers face plagiarism checking. It is necessary to prove the originality of the text, which was written by the author and not copied from other works. It is a specific copyright protection, and anti-plagiarism helps calculate it.

Many professions are connected with the requirements to check for uniqueness – copywriters, journalists, students, candidates, and doctors of science. However, only some know how does a plagiarism detector work, which algorithms are used to calculate the percentage of it, and from which sources articles are taken for comparative analysis.

A plagiarism detector is a program that comprehensively checks the text, comparing it with other publications in the open and own databases. Both single words and entire phrases are checked for similarity depending on the algorithm set. 

When there is a plagiarism detector with percentage, the system outputs the result as a percentage of the original text with repetitions found in the database. Such elements are often highlighted in a different color for clarity and the possibility of correction.

Differences between plagiarism detectors

To understand how does a plagiarism detector work, you should first become familiar with types of plagiarism:

  • Complete – the worst kind of copying someone else’s text, where the content is wholly repeated, the information presented by another author long before the publication of the current work;
  • Partial – individual phrases are taken, which may alternate with whole paragraphs taken from different articles;
  • Unintentional – an accidental overlap of material using the exact phrases, subjects, structure, etc.;
  • Paraphrased is the so-called rewriting when phrases are deliberately rearranged, synonyms are used, and the whole structure is partially changed.

Despite the fact that most plagiarism checkers function similarly, there are certain differences among them that have an impact on the types of plagiarism they can identify. One of the factors that contributes to such differences is the size of the database to which the checker has access. Consequently, there can be significant disparities in outcomes. The second one is quality of the scan. Most free checkers are able to recognize only exact matches. In contrast, high-quality plagiarism checkers utilize a technique known as “fingerprinting” to uncover non-identical matches within reworded or modified texts. Also, plagiarism detector can be of two types: online – opens in a browser and check texts in real-time; and downloadable product – installed on the device, works offline, can be mobile or desktop.

Different systems use their search algorithms, connecting one or more search engines with their databases. For example, using a plagiarism detector with percentage can clearly demonstrate the ratio of successful and unsuccessful checks. According to this characteristic, the maximum allowable score is established, which is accepted by the checking party.

What plagiarism tools can’t determine

Even though plagiarism detectors are always developing and getting better, they still can’t catch everything. If ideas have been entirely changed or translated, plagiarism detectors frequently struggle to detect them. Moreover, internal database text cannot be detected.

Step-by-step procedure for using plagiarism detector

The most popular is considered the online service for checking the text. It is fast, convenient, and relevant to most users. To verify the text, you need to familiarize yourself with the maximum possible amount that can be checked at once. Next, insert the work in an empty field designed for scanning, download file or enter the URL in a separate line. After that, click Start.

How does a plagiarism detector work? The plagiarism checking consists of the following steps:

  • scanning of all text elements;
  • splitting the text into small fragments and phrases, determining the semantics;
  • search for unique values;
  • running the system algorithms;
  • use of databases;
  • connecting search engines to check texts in open sources;
  • the output of the result.

Sometimes, the user can order the report to be sent via email and copy the link with the verified text.


A plagiarism detector is a convenient and practical tool that helps to protect copyrights and get original works without copying and repeating other people’s ideas. For quality scanning and dubbing detection, choosing a reliable, verified system is essential. It will guarantee a complete and reliable result, use its algorithms and a comprehensive database, not share texts with third parties and offer additional services, such as detecting grammatical errors.


What is the acceptable percentage of plagiarism?

The standard rules adhere to a 5-10% norm, but anything higher raises doubts about the work’s authorship. However, it all depends on the subject, the presence of established phrases, and the exact dates that affect the rate.

How is plagiarism detected?

The program scans the text and compares it to existing works on individual phrases, words, and semantics in its internal and open database.