How to Turn On Undo Send in Gmail and Change the Cancellation Window
Undo Send gives you a few seconds to pull back a message right after you hit Send — before it actually leaves Gmail. You can stretch that window to as long as 30 seconds.
Why: Gmail briefly holds every outgoing message before delivering it. During that hold, an Undo link lets you cancel and reopen the draft. Once the window passes, the mail is gone and there’s no recall — so the trick is setting the longest window and acting fast.
Step 1: Unsend a message you just sent
- Send your email.
- In the bottom-left corner, a Message sent notice appears with Undo and View message.
- Click Undo before the notice disappears.
The message reopens as a draft so you can fix or discard it. If the notice is gone, the window has closed and the mail has already been delivered.
Step 2: Change the send cancellation period
By default the window is short. Make it longer so you actually have time to react.
- Open Gmail on a computer.
- Click the Settings gear (top right) → See all settings.
- On the General tab, find Undo Send.
- Set Send cancellation period to 5, 10, 20, or 30 seconds — pick 30 for the most breathing room.
- Scroll to the bottom and click Save Changes.
The Undo link now stays available for the full window you chose after every send.
FAQ
Can I unsend an email after the window closes? No. Once the cancellation period passes, the message is delivered and Gmail cannot recall it. The maximum window is 30 seconds.
Does Undo Send work on the Gmail mobile app? Yes — after sending, an Undo option briefly appears at the bottom of the screen. The cancellation period set on the web applies there too.
Is the recipient notified that I unsent it? No. If you click Undo in time, the message is never delivered, so there’s nothing for the recipient to see.