How does the postal service know when I’m moving?

They don’t! You have to inform them using the change of address form at MoversGuide.USPS.com.

Give the postal service about a week after the selected date to notify them.

The MoversGuide.USPS.com application by the US Postal Service.
USPS mail forwarding is important tool to keep your mail secure and make sure you receive all your mail.

Step 1: Plan Ahead

Plan to complete your change of address at least seven (7) days before you move into your new home.

Step 2: Go To MoversGuide.USPS.com

Browse to MoversGuide.USPS.com and have your debit or credit card ready. Change of address now costs $1.05.

Step 3: Update your Mail Contacts

When you get forwarded mail, make sure you contact the sender to update your address. Take special care to notify any financial institutions, your current state of residence if applicable, any utilities and your medical providers of your change of address.