What FREE alternative ways to Copyscape Premium are there to check for plagiarism?

Many writers use Copyscape Premium to check their content against plagiarism. It is able to catch duplicate content very effectively. You cannot expect the same effectiveness from Copyscape's free version. There are a lot of other online plagiarism checkers available. I have listed many of them here: https://forums.digitalpoint.com/thr...st-of-free-alternatives-to-copyscape.2700629/. Most require you to pay for usage and their free versions have a lot of limitations. You can check content only up to a limited word count or for a certain number of times per day. Also, free plagiarism checkers are not as effectual as paid ones when searching for content copies.
From this, it is clear that using free plagiarism checkers is not an effective option. Also, if one were to use a search engine like Google or Yahoo, there is a limit to the number of words you can search at a time. So, for checking a large block of content, this option either is not feasible.
I am looking for FREE alternative ways to check for plagiarism that are able to catch duplicate content as effectively as Copyscape Premium. Can anyone please advise?

 

scanmyessay.com software called 'viper' not bad , and still a free version. You need a account at the site.

 

OK. But what are the limitations of the free version? Any other free softwares you know?
Basically apart from free softwares and free plagiarism checkers, is there a FREE way to check duplicate content?

 

Paperrater.com does an good job and so does grammerly not sure if that is what your looking for both have free and paid version and i use the free paperrater version and it will check for plagiarized
content.