PlagiarismCheck is a similarity checking software focused on saving educators' time and helping students to achieve better academic results by avoiding plagiarism, improving writing skills with a grammar check, and sharing valuable data. PlagiarismCheck is used as plagiarism checking software for K-12 and HigherEd . The similarity detection mechanism spots not only word-to-word match, but also changes in the sentence structure, synonyms, poor paraphrasing as well as changes from passive to active voice and vice versa. We are able to search though all open resources as well as closed depositories. Moreover, for every client we can create a personal archive of works and search within it, to ensure there is no plagiarism between students' submissions.