Plagiarism, as defined by the University of Oxford, is "presenting some else's work or ideas as your own, with or without their consent, by incorporating it into your work without full acknowledgement." Plagiarism covers all forms of original work, from writing, photography, art works, to songs.

The internet has made the "copy-and-paste" phenomenon even more widespread, with copying someone else's work now as easy as highlighting sentences and pasting them on a Notepad or Word document; or, simply taking screenshots.

For students, academics, researchers and writers, how can plagiarism be avoided in this day and age of data overload, where ignorance does not exempt people from the consequences of plagiarism?

Here are the top five free plagiarism detection tools that anyone can access online:

1. Viper

Viper lets anyone access all of its features for free; in fact, there is no paid version. It double-checks the document against 10 billion resources in its database, and shows detailed accounts on which sentences may have been plagiarized. It is a downloadable application but unfortunately, it's only available on Microsoft Windows for now.

2. PlagScan

PlagScan offers both free and paid versions. Both versions are 100% cloud-based. Its free version, while has a wide array of sources to double-check from, is limited to 1,000 searches at a given session. But it is still worth a try given that it offers comprehensive checks. Its paid version has different plans and prices for private users, schools, universities and companies.

3. Quetext

Quetext is only offered as a free version. Be wary of other websites claiming paid versions are available through these third-party sites. The beauty with Quetex is with its ease of use. It offers a straightforward service where a user pastes texts that want to be checked. The only limitation is files cannot be uploaded; texts could only be copied and pasted.

4. PlagiarismChecker

PlagiarismChecker offers all its features free of charge. It checks both offline and online content, making it suitable for teachers and site administrators who want to check document and text integrity. An added feature is an original work can also be scanned through this site, making it possible to check if someone else has posted one's work elsewhere. It is 100% cloud-based.

5. CopyLeaks

CopyLeaks is specially designed for double-checking online content. The best part, this site has access to over 60 trillion individual web pages on the internet, giving the user a comprehensive scan each time. It also supports multiple languages, and there is an option to add CopyLeaks to one's site so scans are performed automatically. As of now all of its services are offered for free.

While the internet makes it harder to crack down on plagiarizers, it has also offered opportunities for those who take their written work seriously. Thanks to these free online plagiarism checker tools, the crackdown has been made easier.