We have all had the experience of sending an email and immediately regretting it. 


For several year, Gmail has provided a 5-second window during which time you can undo a send. The way this works is that Gmail actually doesn't send until that tiny period concludes. You can increase that window by following these steps.


  1. Go to Gmail
  2. Click the gear icon in the top right
  3. Click "See all settings" button
  4. In the general tab, scroll down until you see "Undo Send"
  5. Chance the cancellation period from 5 seconds to 20 or 30 seconds
  6. Scroll to the bottom of the General tab and click "Save Changes"


The Undo Send section of the General Settings looks like this: