Four free online plagiarism checkers

byIJNetOct 30, 2018 in Journalism Basics

An updated version of this post is available here

“Detecting duplicate content online has become so easy that spot-the-plagiarist is almost a party game,” former IJNet editor Nicole Martinelli wrote in 2012. “It's no joke, however, for news organizations who discover they have published copycat content.”

When IJNet first ran Martinelli’s post, “Five free online plagiarism checkers,” two prominent U.S. journalists had recently been caught in the act: Fareed Zakaria and Jonah Lehrer.

Following acknowledgement that he had plagiarized sections of an article about gun control, Time and CNN suspended Zakaria. Lehrer first came under scrutiny for "self-plagiarism" at The New Yorker. Later, a journalist revealed Lehrer also fabricated or changed quotes attributed to Bob Dylan in his book, “Imagine.”

To date, Martinelli’s list of free plagiarism checkers has been one of IJNet’s most popular articles across all languages. It’s clear readers want to avoid the pitfalls of plagiarism, so we’ve updated the post with four of the best free online plagiarism checkers available to anyone, revised for 2015:


Grammarly gets points for its clean, easy-to-use interface and its efficacy as a plagiarism checker, which compares your writing to more than 8 billion web pages. To check any piece of writing for possible plagiarism, simply drag and drop a file or copy and paste your text onto the web page. Best of all? Grammarly isn’t just a plagiarism checker. The site also checks for spelling and grammatical errors and suggests optimal vocabulary words, allowing you to improve your writing. Grammarly is only available in English, which is one potential drawback for journalists who work internationally.


NoPlag is another great plagiarism checker that compares your writing to articles published online to detect possible cases of plagiarism. To use NoPlag for free without an account, you’ll be able to perform five plagiarism checks per day, with text samples up to 500 words in length. By registering for a free account, you get 20 checks per day with up to 800 words.

Plagiarism Checker

Plagiarism Checker allows you to check writing samples up to 1,500 words in length for plagiarism. If your writing gets marked for potential plagiarism, you’ll be able to review the exact places in your writing that match with content found online.


Want to make sure your website or blog doesn’t plagiarize? Simply copy and paste your URL into CopyLeaks, which uses cloud computing-based algorithms to weigh your content against trillions of websites. CopyLeaks is compatible with any language.

Main image CC-licensed by Flickr via Andres Moreno.