Some free grammar checkers on the Web are downloadable software from GingerSoftware.com and Web-based software at PaperRater.com. Ginger's free version requires manual correction of words according to the software's instructions after a weekly usage limit. PaperRater's free service is limited to six pages of about 300 words each per submission.
Ginger's free software includes use of its basic grammar checker tool to correct grammar, spelling and word usage errors. PaperRater also offers plagiarism detection as part of its free service. Premium services are available from both companies.
Ginger offers a variety of writing-related desktop software and apps related to both writing and enhancing communication via mobile devices. PaperRater's website also includes a tool called Vocabulary Builder, which provides a random word, its definition and numerous sentences containing the word.