Have you ever made a spelling error while writing an article on your WordPress blog, support email, Facebook status, tweet, or Linkedin update? We all have.
Enter Grammarly
Grammarly Chrome Extension will automatically spell-check what you are writing on the web and point out the errors.

I highly recommend using this extension to avoid the spelling errors we all make when we write in a hurry. Also, make sure to check Grammarly official website and take a look at the Grammarly application which allows you to paste the whole text into their editor and check for errors.
P.S. Have you ever wondered why grammar is so important? If you have, this is a good read.