Five free online plagiarism checkers

by Nicole Martinelli
Oct 30, 2018 in Journalism Basics
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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.

It's no joke, however, for news organizations who discover they have published copycat content.

Two prominent U.S. journalists have recently stumbled on this professional peccadillo: Jonah Lehrer who first came under scrutiny for "self-plagiarism" at the New Yorker and Fareed Zakaria, who was suspended from Time, CNN and the Washington Post for "unattributed excerpts."

Some news organizations use pricey software to check for plagiarism, but if you're in a small newsroom or run a blog, these free versions will give you an idea of whether you have fresh talent or a veteran copy-and-paster. Another reason to check them out: if you want to know how original your writing is, run it through a checker--they're great cliche-catchers, too.

Here are IJNet's picks:

Plagiarisma This content checker is our top pick for language support and versatility. Sign up for free with your Facebook account and you can paste in text, check a url or upload files in 190 languages. Aside from checking the web, Plagiarisma can also delve into Google Scholar for articles, patents, legal opinions and journals as well as Google Books.

Plagtracker The free version checks your text, up to 5,000 characters a month, against 14 billion web pages and 5 million academic papers. Compared to competitors, the free version was sluggish, it took about two minutes to process our 500-word post. While it correctly picked up a partial quote as repeated over and over, it did not always pick up content that had been published on our partner sites. Plagtracker has the cleanest interface of the bunch and the results are understandable at a glance. Available in German, French, Romanian and Spanish with Italian in development.

Duplichecker The website allows you to check copy by either pasting it or uploading a .txt file, then compares it sentence by sentence with Google, Yahoo or MSN search. It works quickly and correctly spotted our duplicate partner article--as well as several unauthorized reprints--but lower on the results page were many articles matching any of the words, not the specific phrases. Since it breaks down the article into sentences for you, it's much faster than using a search engine on your own. Available in English only.

Copyscape The free version of this content checker works by seeking out duplicate pages, so it won't help you much before publishing, but it can help if you need a quick take on what you have already published. Premium versions include copy searches and duplicate alerts.

Google search This one's obvious, but we're including it as a reminder for a couple of reasons. Although you can only check short passages--the search engine limits queries to 32 words--it allows you to test sentences in all of the 46 languages Google serves, from Afrikaans to Vietnamese. A quick run of a few quotes would let you know whether the text requires more scrutiny.

Image CC-licensed via Flickr.