"Undo Send" Now Available from Gmail
Got emailer’s remorse? Google is now offering the “Undo Send” option to the web version of Gmail. The “Undo Send” option allows you to cancel an email once it’s been sent between 5 and 30 seconds after it’s been dispatched. Once you’ve hit “send”, a yellow bar confirms it’s been sent and provides the option to view the message or take it back.
How to enable “Undo Send” in Gmail
“Undo Send” will appear in the main “General” tab of your email settings. If you already had the option turned on in Labs, then it will still be on by default. If not, you’ll need to check the little box next to “Enable Undo Send.”
Wired explains further:
Navigate to your “Settings” pane in the menu directly below your profile photo and you’ll be given the option to “Enable Undo Send,” along with a drop-down that lets you customize the cancellation period for the feature: five, 10, 20 or 30 seconds.
To note from Google
To give you time to undo, Gmail delays sending the message for a few seconds. So if you don’t select “Undo” within the time limit, your message will be sent. “Undo Send” may not work if you experience connection issues. Additionally, “Undo Send” is not available for the Gmail mobile app.