Top 11 Free Online Plagiarism Checkers For Students and Instructors

Jul 14, 2019

Jul 14, 2019 | Reviews

As a good student, you do everything to make sure you submit original work.

However, you will often find yourself second-guessing yourself:

‘I did do the assignment myself. But what if some other student somewhere had the same idea? What if I did not do a good job of paraphrasing my sources?’

You have two options:

Submit the work and hope for the best.

Or, be sure your work has the required amount of uniqueness using a plagiarism checker.

That you are on this page means you are considering the second option.

Unfortunately, you might not know which sites to use to check for plagiarism or are not ready to spend on plagiarism-checking software.

Read on to find out more about the best free online plagiarism checkers.

What Is Plagiarism?

Plagiarism is copying another person’s idea and presenting it as your own without giving the owner the credit they deserve.

Unlike copyright infringement, plagiarism is not punishable by law: Plagiarism is more of an ethical offense.

However, universities do punish students for plagiarism.

Plagiarized content in your academic paper can result in rejection of your work, low grades, or even discontinuation.

Types Of Plagiarism

Plagiarism can be classified into the following categories:

  • Direct plagiarism: refers to copying another person’s published work word for word without giving them credit.
  • Accidental plagiarism: refers to forgetting to provide a citation for another person’s work unintentionally.
  • Self-plagiarism: this type of plagiarism is when you copy your own previous work or produce work influenced by your previous work.
  • Outsourcing: paying someone else to do work for you and present it as your own.

How To Avoid Plagiarism

The following are some tips on how to avoid plagiarism:

  • Paraphrase

You have found the perfect material for your paper.

The next step is to read and understand it, then write what you have understood in your own words.

Do not copy word for word.

In fact, you should not lift more than three consecutive words from your sources.

  • Read more than one source.

If you use only one source for your assignment, you will likely copy information from that source intentionally or unintentionally.

To avoid that, read multiple sources, and remember to cite and reference the ones with the most relevant information.

  • In-text citations

If you have to quote directly from your source, use in-text citations.

Aside from helping you avoid plagiarism, in-text citations improve the credibility of your work by showing your reader that you actually conducted research.

Remember to use the citation guidelines of the academic writing format (MLA, APA, Vancouver, Harvard, etc.) specified for your paper.

  • Referencing

Another way to avoid plagiarism, especially if you have used direct quotes from your sources, is through references.

Actually, the referencing section, or bibliography, is compulsory in most academic papers.

Just like citations, the academic format dictates the referencing guidelines.

Top 10 Free Plagiarism Tools

The following are the best free plagiarism checkers for students and teachers.

  1. Plagscan

plagscan Plagiarism Checker

Plagsacan is a highly accurate plagiarism detector trusted by many students and teachers.


  • Allows you to upload documents or copy and paste the text.
  • The plagiarism report includes percentages, a list of the sources of the plagiarized text, an overview highlighting the copied content.


  • You can only scan the first 2,000 words for free.

2. Quetext

Quetext plagiarism checker

Quetext is a free plagiarism checker that highlights plagiarized content and provides the percentage of plagiarism.


  • Generates an easy-to-understand plagiarism report.
  • Features a built-in citation tool


  • The trial version only allows three checks of 500 words each.

3. Viper

viper plagiarism checker or scan my essay

Viper is a free plagiarism checker dedicated to academic papers (a free Turnitin alternative). Viper changed its name to scan my essay plagiarism checker.


  • Compares your text against many sources, including online content, books, and journals
  • Specially designed for educational purposes.


  • Not as effective as premium plagiarism checkers such as Turnitin and Grammarly.

4. Plagiarisma

plagiarisma plagiarism checker

Plagiarisma is a multipurpose tool that scans for duplicate content, rewrites the text, and highlights grammar errors.


  • Upload files or copy and paste the text
  • Supports more than 190 languages
  • Checks grammar.


  • Slower scanning compared to other sites
  • Limited free scans


This plagiarism checker is user-friendly and completely free.


  • Provides an easy-to-understand step-by-step approach
  • It is entirely online; no download is required.
  • Has a ‘for author’s section that you can use to check if someone else has published your work


  • Only available in Google and Yahoo browsers.

6. Copyleaks

Copyleaks is a plagiarism detection tool that also has a copyright protection feature.


  • Check for duplicate content in your work and check if your work has been used by someone else.
  • Has a bulk search feature for teachers that allows scanning up to 100 papers simultaneously.
  • Has a mobile app


  • The free version allows scanning only 2,500 words per month.

7. Unicheck

This website is a premium plagiarism checker with a free trial version.


  • Compares your work against 16 billion sources
  • It allows you to upload a document or copy and paste
  • The software supports different file formats, such as .doc, .txt, .pdf, and .zip
  • Supports multiple languages, including English, French, Greek, German, and Russian


  • The free trial offers a limited number of scans.
  • Using the free version, you can only scan 500 words at a time.

8. Duplichecker

Duplichecker is an entirely free plagiarism checking tool.


  • You can upload a word document or copy and paste the text.
  • You can scan more than 50 documents in a day, a feature that makes it convenient for teachers as they have to scan multiple papers at a time.


  • A scan has a 1000-word limit.
  • To scan more than once a day, you have to create a free account.

9. SmallSEOTools Plagiarism Checker

SmallSEOTools features, among other tools, a completely free plagiarism checker.


  • Has other tools to help students and teachers, such as spell checkers.
  • It is fast – generates a plagiarism report in seconds.
  • Allows you to upload documents from cloud storage such as Google Drive and DropBox.


  • Has a limit of 100 words per search

10. PaperRater

PaperRater is a plagiarism detection tool that offers a free trial version.


  • Multipurpose; check for duplicate content, grammar, and build your vocabulary.
  • Fast; provides an accurate plagiarism report in seconds
  • Designed by industry experts


  • You can only scan five pages for free.

11. Prepostseo

It is very easy to use as users have to upload the document or paste the text in the box, and it scans it from the data store in its database to check plagiarism.



  • Checks grammar.
  • Then Users can upload documents in DOC, DOCX, PDF, TXT, etc., or copy-paste the URL.
  • Provides safety of the data
  • Generate plagiarism reports which you can download in PDF and HTML format.


  • Limited free word access up to 1000 per search. If you register, it will allow more than 1500 words per search.

When To Use Free Plagiarism Checkers?

Most free plagiarism checkers do not detect all plagiarism.

That said, the free trial versions of the premium plagiarism checkers are more accurate.

Free plagiarism checkers are convenient when:

Checking plagiarism in short documents, i.e., 1 to 3 pages.

You want to test the tool before purchasing the premium version.

You are confident you did not plagiarize any content but want to be sure.


Academic institutions are now stricter about plagiarism.

Therefore, it is in your best interest to run your work through a plagiarism checker before submitting it.

You can use any of the free plagiarism checkers listed in this article.

It is always safe to avoid plagiarism in the first place by following the anti-plagiarism tips shared at the beginning of this article.