ProWritingAid is your online writing editor and personal writing coach. 

This free version runs on the first 500 words of your document. Full reports are available by purchasing the premium version, or by signing up for a 14-day free trial.

Of course it checks your grammar but it does much more to help you improve your writing:

- Check for consistency of spelling, hyphenation, and capitalization;
- Eliminate clichés and redundancies;
- Check for plagiarism and unoriginal content;
- Online grammar and spelling checker;
- Improve readability;
- Find overused words;
- Improve dull paragraph structure;
- Find repeated words and phrases;
- Eliminate vague, abstract, and complex words from your writing;
- High quality copy-editing and proofreading services;