A plagiarism checker is a program that scans text to see if it contains ideas or sentences that have been taken from other sources. If your work is very similar to that of another author, you will be notified that this is the case. This can help you to avoid the duplication of ideas and to find out who of the origin is the original author. The best thing about this free tool is that it is very easy to use. You just have to paste the text you want to check into the box and click on the button.