How to Avoid Mail Being Returned to Sender

Returned mail costs time, money, and can cause missed deadlines. USPS returns mail for various reasons including incorrect addresses, insufficient postage, and recipient issues. Understanding why USPS returns mail and how to prevent returned mail saves frustration and ensures your important correspondence reaches its destination. This guide covers USPS return to sender codes, the most common causes, and how to avoid them.

Common Reasons Mail Is Returned

USPS marks returned mail with specific codes indicating the reason. The most common USPS return to sender codes are:

• Insufficient Address: Missing apartment number, wrong street name, or incomplete information
• No Such Number: The street number does not exist
• No Such Street: The street name does not exist in that ZIP Code
• Not Deliverable as Addressed (NDAA): General address problem preventing delivery
• Attempted Not Known: Recipient name not recognized at that address
• Moved Left No Address: Recipient moved without forwarding
• Refused: Recipient rejected the mail
• Insufficient Postage: Not enough stamps for the weight or service
• Unable to Forward: Forwarding order expired or not on file

Address Verification Before Mailing

Verify addresses before mailing to catch errors and prevent returned mail:

• Use our free Address Validator to verify full addresses
• Use our ZIP Code Validator to confirm ZIP codes match cities
• Include apartment, suite, or unit numbers
• Verify PO Box numbers with the box holder
• For business mail, confirm the company is still at that address
• Ask recipients to confirm their current mailing address

Proper Address Formatting

USPS prefers addresses formatted as:

• Line 1: Recipient name
• Line 2: Street address (number, street name, apt/suite)
• Line 3: City, State ZIP Code

Formatting tips to avoid undeliverable as addressed mail:

• Use standard abbreviations (ST, AVE, BLVD, APT, STE)
• All caps improve machine readability
• No punctuation is preferred
• Include directionals (N, S, E, W, NE, SW) when part of the address
• Put secondary unit info (Apt, Suite) on the same line as street address if possible

For detailed guidance, see our how to address an envelope guide.

Ensuring Correct Postage

Insufficient postage is a preventable reason for returns:

• Weigh your mail before adding stamps
• First Class letters: 1 oz limit for standard stamp; add postage for additional ounces
• Large envelopes (flats) cost more than letter-size mail
• Square envelopes require a non-machinable surcharge in addition to regular postage
• Rigid or uneven thickness requires extra postage
• When in doubt, take it to the post office for weighing

Dealing with Recipient Moves

Mail is returned when recipients move without forwarding:

• Confirm addresses annually for regular correspondents
• For business mail, use address update services
• USPS forwards First Class Mail for 12 months after a change of address is filed (magazines and periodicals forward for 60 days only)
• After 12 months, forwarded mail is returned if no permanent update is filed
• Add "Address Service Requested" to get updated addresses from USPS (fee applies)

Learn more in our USPS change of address guide.

Name and Recipient Issues

Mail may be returned if the recipient is not recognized. Understanding "Attempted Not Known USPS" codes helps prevent this:

• Use the recipient's full legal name as it appears on their mailbox
• For married recipients, confirm which name they use for mail
• Businesses must be addressed to the registered business name or a known employee
• For c/o addresses, ensure the c/o party will accept mail for the recipient
• PO Box mail must match an authorized name on the box

Return Address Best Practices

Always include a return address so undeliverable mail comes back:

• Place return address in the upper left corner of the envelope
• Include your full name, street address, city, state, and ZIP
• Use a consistent return address so you receive returned mail
• Without a return address, undeliverable mail goes to the USPS Mail Recovery Center in Atlanta

Special Situations

Military mail (APO/FPO/DPO):

• Use exact format provided by service member
• Include rank and unit information exactly as specified
• Verify deployment location has not changed

International mail:

• Include country name in English on the last line
• Follow destination country's address format
• Use correct international postage
• Customs forms required for packages

Rural addresses:

• Rural routes may have converted to 911 street addresses
• Verify current address format with recipient
• Some areas use both formats; street address is preferred

What to Do When Mail Is Returned

• Read the USPS marking to understand why it was returned
• Verify the address with the recipient before resending
• Correct any postage issues
• If address was correct, contact the recipient to confirm they still receive mail there
• For repeated returns, consider calling USPS or the destination post office

For more details on what happens to returned mail, see our return to sender guide.

FAQs

Related Tools & Guides

• Address Validator Tool – Verify addresses before mailing
• ZIP Code Validator Tool – Check if a ZIP code is valid
• Return to Sender Guide
• How to Address an Envelope
• ZIP Code Lookup Guide
• USPS Change of Address Guide
• USPS Lost Mail Guide