Track My Words is a free Google Add-On that automatically tracks your writing stats and words per minute.
All you need to get started is to add the Track My Words Add-on to Google Docs, and register with this site to get a free license key.
Tracking your writing will allow you to see what time of the day you write most efficiently, enable you to set consistent goals, and more.
Your daily writing is displayed in beautiful charts to make it easy for you to see when you write most quickly and most consistently.
Track your words per minute over time - compete with yourself to write more efficiently.
See which days you aren't writing, and try and boost your output.
View your progress at any point during the day