Returned mail is a critical operational burden for businesses and a frustration for individuals. The United States Postal Service (USPS) attaches a yellow sticker (also popularly known as a “Nixie Label”) whenever it cannot deliver a mailpiece. This label contains specific USPS returned mail codes that explain the specific reason behind the non-delivery. 

Deciphering these codes can be confusing. The non-delivery could be because of anything, including a “vacant” property, “insufficient” address, or a recipient who has “Moved”. Businesses must understand these codes to maintain database hygiene and avoid resource wastage. 

This blog is the perfect place to get a comprehensive reference to USPS returned mail codes. So, you learn the reason behind returns and take necessary steps to resolve them. We will also look at some tips to avoid returns in the first place. Let us begin!

A recent USPS audit found 40,000 undelivered mail items across two post offices in Columbus, Ohio. It isn’t surprising that the Post Office cannot deliver every package or envelope successfully. Simply because it stores some items for redelivery and returns others to the sender with USPS return mail codes that tell you why.

So, how can you decrypt these codes and resolve the problem?

And how to avoid getting mail returns in the first place?

Keep reading further to find the answers and improve your logistics system!

TL;DR

• USPS return mail codes such as “Not Deliverable as Addressed” and “Insufficient Address” explain non-delivery and enable corrective action.
• Implementing an Address Verification solution with NCOA and CASS identifies address issues before mailing to reduce costs.
• Using verified address databases ensures accurate delivery, saving postage resources and preventing waste.
• Fixing common errors like incomplete or illegible addresses is crucial for improving delivery success.

Key Takeaways 

• Nixie Labels can work as diagnostic tools to identify the root cause of delivery failures. 
• Businesses must have effective management to differentiate between fixable errors and dead leads to prioritize their data cleansing efforts. 
• Ignoring USPS returned mail codes might compound into wasted printing, material, and manual labor to process physical returns. 
• It is a good idea to sort returns by code type to update data in CRM or mailing lists.

We have listed below a series of USPS returned mail reason codes and their solution to help you understand them better. Thus, you can be aware of the issues and take the necessary steps to avoid them the next time you send a mailpiece. 

Not Deliverable as Addressed – Unable to Forward (UTF)

It is one of the most recurring USPS return mail codes senders get, and means that the carrier cannot deliver the item to the address on the label. The primary reason is that the addressee has shifted to a different location, but:

• There is no mail forwarding address.
• The addressee has not filed a change-of-address (COA) request yet, so USPS does not know their new address,
• The forwarding request is no longer functional,
• The sender or addressee failed to pay for the forwarding postage,
• Or the sender endorsed the item with the words ‘DO NOT FORWARD.’ 

Solution: Run your addresses through NCOA software before shipping to send items to the correct, updated addresses.

Insufficient Address (IA)

This UAA code is also among the most commonly-seen USPS return-to-sender codes and means that:

• Some essential part of the delivery address is missing, like the city, route number, state, street address, ZIP code, etc. 
• A missing PO box, suite, or floor number restricted the carrier from finding the intended destination. 

Solution: If you see such USPS returned mail codes, add the missing details and reship the item. 

 Also Read: What Is Third-Class Mail

Returned for Better Address (RBA)

The ‘Returned for Better Address’ Nixie code is similar to ‘Insufficient Address’ It means the package or envelope information isn’t enough for delivery. 

Solution: Modify the address a bit to offer more details to the carrier, or use an Address Verification solution to automatically update the address.

No Such Number (NSN)

You may also get USPS returned mail codes saying USPS didn’t find the apartment or house number you wrote on the item. For instance, if you write 52 Olive Street, but there are only houses 11 to 45 in that area. In such scenarios, the Post Office may need to send back your parcels unless they run a name search and find the correct address in their system. 

Solution: Always check the numbers in your addresses for errors, swaps, extra zeroes, etc., to avoid getting such USPS return mail codes for such minor mistakes. 

 Also Read: Automated KYC Verification

Returned For Postage (RFP)

Imagine you forgot to affix the correct number of stamps covering your postage costs. The Post Office does not process such items from the start and returns them to let you apply the postage and reship the same. Unlike other USPS returned mail reason codes, you only have to pay the postage on time in this situation. 

Solution: Calculate the correct postage using the USPS postage calculator and attach the correct postal fees before you drop off your items in a mailbox. 

Attempted – Not Known (ANK)

This code says that USPS attempted the delivery but could not deliver because the addressee does not live at the address. It is one of the most complicated USPS return-to-sender codes to decrypt. NCOA or CASS does not guarantee whether a person resides at a specific address if they didn’t file an address change request. 

Solution: Combine data from multiple resources to confirm your intended recipient’s address and avoid such USPS return mail codes on your items. If you want to avoid the legwork, use PostGrid’s direct mail API for mailing instead. 

No Mail Receptacle (NMR)

Have you seen people living in gated houses with their mailboxes near the door instead of the gate? Also, some customers living in gated communities have a joint mailbox. 

The USPS returned mail codes that say ‘No Mail Receptacle’ mean that the carrier cannot deliver the item to the recipient’s mailbox because of the abovementioned reasons!

Solution: Mention the joint mailbox number or address instead of a recipient’s address. 

Illegible (ILL)

Some USPS return mail codes are easily avoidable, like this one. It says that the address is illegible or impossible to read. You may face this problem only if your staff writes every address manually using a pencil or pen. Writing addresses instead of printing may also cause issues because of weather conditions. For instance, your package can get damp, and the ink might blot. 

Solution: Print and stick address labels to your mailpieces and cover them with clear tape. 

 Also Read: What Does FIPS Code Mean

Moved, Left No Address (MLNA)

Seeing these USPS return to sender codes is not uncommon because 9.8% of Americans move yearly. Many people change their residence or office address but fail to report them to USPS. Thus, the Post Office has no records of their addresses, leading to mail returns. 

Solution: Use an NCOA-processing, CASS-certified solution to check the details before mailing to avoid getting these USPS return mail codes on your parcels. 

Temporarily Away (TA)

Sometimes, your recipient is unavailable at their homes for a short span. Perhaps, they went away for a vacation or because of other reasons. Most people avail of the mail forwarding service at such times, letting USPS deliver their mail temporarily to the new address. But, if not, the Post Office returns the item to you with USPS returned mail reason codes so you can ship again after a few days or weeks. 

Solution: Confirm the recipient’s availability beforehand and suggest they use the Informed Delivery postal feature to stay updated regarding incoming mail. 

Vacant (VAC) 

The recipient does not live at the mentioned address any longer, and the apartment or house is vacant. 

These USPS return mail codes are simple and upfront to understand. And a DPV address check can help you spot all vacant addresses effortlessly. 

Solution: To avoid receiving mailpieces with vacant USPS returned mail reason codes, print, and mail using online solutions like PostGrid. 

 Also Read: What is a Mailing House?

Outside Deliverability Limits (ODL)

Some rural places or areas with adverse weather conditions are non-serviceable by USPS. If you ship items to such addresses, the Post Office endorses them with USPS returned mail codes and returns the mailpieces to you. 

Solution: Check if you mistakenly mentioned an incorrect city or street name. If not, use a different carrier or try finding a PO box number to mail to such recipients. 

Refused (REF)

The addressee didn’t accept the item or refused to pay for the postage due. 

Solution: You cannot avoid such USPS returned mail codes, primarily for those customers who order COD items. For shipping marketing items, try filtering out recipients who don’t wish to receive mail from you. 

Box Closed – No Order (BC)

If you ship to a PO box address and get such USPS return-to-sender codes, it means that:

• The PO box is no longer working because of the non-payment of fees. 
• The recipient stopped using the PO box, and there is no forwarding address. 

Solution: Update your lists from time to time to get the new addresses of your customers and prospects. 

Deceased (DEC)

The USPS returned mail codes that say ‘Deceased’ are pretty straightforward. Unless you address an item to the ‘Occupant,’ the carrier sends it back. 

Solution: Use CASS records to remove entries of deceased customers or update the addresses with someone else’s name (like a family member). 

No Such Street and No Such Office in the State (NSS/NSO)

These two USPS returned mail reason codes mean you mentioned a street or Post Office name that is non-existent.

Solution: Cross-check your street addresses, especially if they are similar to other street names. 

 Also Read: What Does Out For Delivery Mean In USPS

Returned to Sender Due to Addressee’s Violation (VIO)

There can be several reasons for getting these USPS return mail codes, but most involve false representation by the addressee. 

Solution: You must not reship items to these addresses because you may get them back again. Instead, remove these entries from your mailing lists to prevent these USPS returned mail codes and save on postage. 

Unclaimed (UNC)

Items with the ‘Unclaimed’ USPS return-to-sender codes could suggest that the recipient does not want the mailpiece or is unaware of its receipt. If the recipient does not take out their received mailpieces for a long time, a carrier might take them back to the Post Office. 

Solution: Use an address checker to see if you sent the item to the correct recipients. 

 Also Read: USPS Certified Mail Costs & Rates 2024

3 Commonly Misunderstood USPS Returned Mail Codes

Return Code 1

When people see an insufficient address code, they often assume that the address is completely missing or left blank. However, it can be triggered by multiple reasons, such as a missing apartment number, a typo in the street name, or not including directional information.

Return Code 4

People often assume it is a delivery error. This is because it displays the street exits, but the house or building does not. However, it means that the address is invalid.

Return Code 10

This error indicates that the person does not live at that address or is not recognized by it. However, people often think it is a carrier mistake.

How to Handle and Prevent USPS Returned Mail Codes 

Use Verified Address Database

To ensure accurate delivery on the first attempt, use CASS-certified Address Vrification software. It will standardize and validate addresses according to USPS standards, correctly format them, and provide real-time geolocation-based autocomplete suggestions. CASS-certified software ensures your address list meets USPS standards, making you eligible for reduced postage rates.

Update Databases With National Change of Address (NCOA) 

People around the USA tend to move houses frequently, and unless your mailing list is updated, the item will land at the wrong doorstep. The NCOA contains a list of people who have requested a change of address with USPS. You can visit the NCOA website to get the latest address.

You can also use an NCOA-certified solution to cross-check every entry through NCOA and provide you with the latest address. If you are involved in bulk mailing, running the check every 95 days is essential to stay compliant with USPS regulations.

Add All Necessary Elements

For the address to be considered complete and deliverable, you must mention every element. Make sure to include the:

• Street name
• Street number
• Apartment or suite number
• City
• State 
• ZIP+4 code

The USPS also recommends using standard abbreviations, such as “St.” for “Street” and directional indicators like “NW” for “Northwest.”

Use Endorsements Carefully

The USPS provides an ancillary service endorsement on mail, instructing you on what to do if the address is undeliverable. For instance, “Return Service Requested” means you will get the mail back, along with the reason, which will help you update your list. You can also opt for Address Service Requested, which will provide forwarding information.

There is also a Change Service Requested service, which provides electronic notification. Choosing the proper endorsement will help prevent returned mail, avoid wasting postage, and maintain list accuracy.

Isolate and Categorize the Return Mailers 

You should not throw away the return mail. In fact, return mail management is a critical process in successful organizations. We recommend that you sort the items by code type. It will give you better clarity about the type of return mail and update your database. Besides, you will also be able to take necessary actions on such mailers for each code.

What Is the Importance of Understanding USPS Returned Mail Codes for Businesses?  

Cost Efficiency 

Every returned mail adds up to your mailing budget. Think about it, you are paying unnecessarily for postage, printing, paper, and handling. Then, you also need to consider the labor you need to handle the returns. Hence, businesses must understand the USPS returned mail codes and actions to resolve them. Apart from saving money, you can reduce your carbon footprint by avoiding unnecessary mailing.

Customer Relationships 

Your customers expect timely communication. Besides, you cannot delay invoices, statements, and other critical correspondence to your customers. Analyzing these codes helps you get to the root cause of returned mail and keep your communications timely. As a result, your business maintains trust and reliability with customers. 

USPS Compliance and Postage Discounts 

USPS expects bulk mailers to have a lower UAA rate. In this way, the postal carriers avails postal discounts for businesses. Besides, USPS constantly monitors your return rate. So, higher returns might make your account susceptible to reviews. You might also lose your ability to use Move Update standards. It could mean losing access to automation pricing.

Fraud Detection and Risk Management

Some USPS returned mail codes directly indicate signs of fraud or malpractice. For example,  “Vacant” or “No Mail Receptacle” might show a synthetic identity or fake address in use. A code like “Returned Due to Violation” clearly highlights false representation or law violations. Besides, financial institutions should always be aware of “Deceased” codes to avoid identity theft.

Checklist for Preventing Mail Returns Before Sending

Verify Recipient Details

• Write the full and correctly spelled name.
• Add house, building, street name, and apartment number.
• Use the USPS ZIP code lookup tool to ensure the city and state match the ZIP code.

Use standard USPS abbreviations

Use Verified Mailing Address

• Use the USPS ZIP code lookup tool to check if the address is deliverable.
• Avoid using P.O. boxes if you use a private carrier like FedEx or UPS.
• If the recipient has recently moved, check if they have updated their address with the NCOA.

Choosing the Correct Postage

• Weigh your mail and make sure to apply the right amount of postage.
• Add the correct label if you are using a special service, such as Certified Mail or Priority Mail.

Label and Package it Properly

• When printing, use a clear font, or write in all caps if you choose to write by hand.
• Make sure you include the return address in the upper left corner.
• Ensure the address is aligned and readable when the envelope is upright.
• Make sure to use a sturdy envelope and tape all the edges securely.

What Is USPS CASS and NCOA? How They Can Reduce Return Mail?

Coding Accuracy Support System (CASS)

CASS is a certification process that helps users to standardize addresses according to the official USPS format. It means the system can fix typos, add missing information, and verify the validity of a postal address. So, your mailers could successfully reach their destination instead of returning with Nixie Labels.

National Change of Address (NCOA)

The NCOA database holds approximately 160 million permanent change-of-address records filed with the USPS. A solution with NCOA can cross-reference your mailing list against this database and update the records if necessary. So, you can avoid delivering mailers to your recipient’s old address. 

How Can Businesses Verify Addresses in Bulk to Avoid Return Mail? 

Now, you know what USPS returned mail codes are. But how to avoid such situations in the first place when you are working with thousands of addresses? Manually checking each customer record against USPS data is not feasible for a business. You shouldn’t spend that much time and resources.

The best answer is a modern CASS-certified Address Verification software to optimize this process. PostGrid’s Address Verification API can directly integrate with your CRM or database to validate entries and standardize inconsistencies against the official USPS records in seconds. So, you only need to upload your bulk mailing list, and the solution would fetch validated and updated addresses in no time. Hence, you get clean records to reduce mail and save overhead costs.

Contact us now to learn how to validate and update addresses in bulk to lower mail returns!

PostGrid’s automated direct mail services assist you during every stage of your printing and shipping cycle. It allows you to prepare and produce on-demand and bulk mailing items according to your preferences. So, no more purchasing paper stock, packaging items, ink cartridges, stamps, labels, etc. Nor do you need to look for a printer to print your orders!

Also, PostGrid allows you to ditch USPS return mail codes by noticeably reducing the number of returns! Our solutions ensure you avail of a 99.99% deliverability ratio by verifying your addresses before mailing. 

Currently, we offer two pricing plans to our clients with varying needs, and they are:

• Starter: You can use our Starter membership for free and only pay the per-piece prices for the item you mail. Thus, you have more flexibility to ship up to 500 mailings every month without committing to anything. 

You get mail tracking, access to our standard print delivery network, and up to ten design templates with this plan. Additionally, you can quit seeing the USPS returned mail codes by validating your addresses before shipping.

• Enterprise: The Enterprise membership offers many more features, like HIPAA compliance, native integrations, unlimited templates, etc. Also, you can verify innumerable addresses before mailing to avoid the USPS return mail codes using this plan. 

Talk to sales now to discuss your requirements and get the best quote.

 Also Read: When Does USPS Stop Delivery?

Getting mail returns with USPS return-to-sender codes or yellow Nixie labels can be distressing. They tell you something is wrong, and you need to pay again to reship the items correctly. It means—a loss of time, money, resources, manual effort, and brand reputation.

PostGrid’s direct mail API can allow you to prevent these problems and ship effectively. Everything is online and automated, so you only need to push a few buttons on your device, and voila!

Click here to learn more about how we help clients not get USPS returned mail codes and ship accurately.

 Also Read: What is a Mail Stop Code?