Here’s an unfortunate thing to write in an email to a client:

You’ll receive copies of the signed contacts by Friday afternoon.

Sure, they’ll probably figure out that you meant “contracts,” not “contacts.” But they might also make a mental note that they’ll need to double check your work since your attention to detail seems to be lacking. Not a great way to start a business relationship.

To err is human, but when you’re trying to make a good impression, grammatical errors and typos undermine your work. In fact, according to a Grammarly study of LinkedIn profiles, people who failed to progress to a director-level position within the first ten years of their careers also made 2.5 times as many grammatical mistakes as their director-level colleagues.

In a perfect world, we’d all have time to proofread and polish everything we write. But most of us have a million things on our to-do lists, and the precious minutes it takes to ask Google if we’re using “affect” and “effect” correctly can be a tough sacrifice. That’s why over 30 million people have turned to Grammarly, a personal editor that helps you make sure everything you write is clear, effective, and mistake-free. The best part? It’s free.

Grammarly works on Gmail, LinkedIn, Facebook, Twitter, and everywhere else you write in the form of a browser extension. You can also download the Grammarly Microsoft Add-in to use in Word and Outlook. As you type, Grammarly will check what you write and let you know if there’s something you need to fix. (Are you an always-on-the-go type? Check out the Grammarly Mobile Keyboard and say goodbye to textfails.)