Plagiarism: Free plagiarism checkers

"This is a free service designed to monitor your RSS feed and find where your content has been republished in the blogosphere. We automatically notify you when a new post of yours is copied to another feed, we also build an overview page you can view to see how/when/where your content is being duplicated, quoted or plagiarized."

Free version allows users to paste entire papers into a search box. Will find exact sentence matches. A premium version, for a subscription fee of $8 per month, claims to increase the accuracy of the scan and allows users to upload Microsoft Word documents. After the daily limit of uses has been reached (1,000 uses daily), the service ceases to operate until the following day.

"Some features that most students and teachers find interesting with the Scholar Google is its ability to search not only plagiarized phrases but also correct missing quotation marks and citations. This software scans your research paper, essay, coursework or dissertation completely from its database of internet resources, past exam papers, past essays, old dissertation papers and published journals. Google Scholar and Google Books has a large databases of past and current published materials, studies and articles that makes the software more accurate in tracking down duplicate content. Always make sure that your essay is not containing plagiarism before final submission to tutor."

It's not free, but it is relatively inexpensive. Grammarly detects plagiarism and corrects over 400 different types of writing issues. Avoid plagiarism by checking for originality and generating citations. Improve word choice with context-optimized synonyms. Instantly proofread your texts and corrects over 400 different types of errors.
Integrates with Microsoft Office® ; Grammarly works great inside Microsoft™ Word®
and Outlook®."

"HelioBLAST is a free service provided by HelioText. The HelioBLAST text similarity engine finds text records that are similar to the submitted query. HelioBLAST uses our super-fast search engine, and this service is provided to demonstrate what can be done using text similarity searching. HelioBLAST can be customized to search a particular database or multiple ones; and proprietary databases can be created for individual clients.

Here, your query is searched against the citations (abstract and titles) in Medline/PubMed. Submissions are limited to 1,000 words, so we recommend your query should be an abstract or paragraph."

Allows for document submissions (all file formats) and webpage (url) submission. When you click the Submit button, this site links you to a Google search results page. The page has a list of websites that contain one or more of the phrases you typed in. Allows you to search for several phrases from a student's paper at the same time without having to type quotation marks or special operators, which most search engines require if you're trying to look for exact copies of a student's writing.

TinEye is a reverse image search engine. You can submit an image to TinEye to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions.

Free trial for 14 days.

"Welcome to Viper - a leading alternative plagiarism checker which, using its range of powerful features, will help you check for plagiarism and duplicate content in your work. From individual students to lecturers and institutions, Viper is the plagiarism checker of choice for thousands of people every month."