USPS Validation Code


March 24, 2024

A significant location, such as a move out of state, requires meticulous planning. You’ve got to sort through your belongings, inform your landlord of your planned departure, and arrange the logistics of your voyage.

Amid this whirlwind of tasks, you must also remember to add a crucial item to your relocation checklist – submitting a change of address (COA) form to the United States Postal Service (USPS).

Why is this task essential, you might ask? It’s how you ensure your mail and packages keep pace with your life’s journey. The COA form signals the Postal Service to reroute mail items from your old home to your new address.

However, before USPS can seamlessly transition every piece of mail to your new dwelling, it has a critical task: address validation or verification. The U.S. Postal Service must determine if it can deliver your valuable mail items to your new location without a hitch.

That’s where validation codes come into play. These unique alphanumeric keys help USPS confirm if it has your correct and active mailing address in its address database.

This article breaks down the complexities of USPS validation codes and how they can help facilitate your mail and packages during the relocation process. It also explores the purpose and importance of address validation, including USPS’s methods to maintain data accuracy.

For additional information on USPS validation codes, visit the USPS website at Alternatively, you can talk to a Postal Service representative at your local post office, which you can find using’s search tool.

What Does USPS Validation Really Mean?

Whether you’re an individual looking to update your address information for incoming mail or a business owner managing a database of customer addresses, ensuring the accuracy and deliverability of those addresses is essential.

With the United States Postal Service address validation, you can determine if a specific mailing address is a USPS-valid address by comparing it against the USPS address database. 

A USPS-valid address refers to one that follows USPS address formatting guidelines.

Root Cause of Bad Address Data

A USPS-valid address must have the following elements:

  • All capital letters
  • When applicable, the company name, apartment, suite, or house number
  • USPS-recognized acronyms and abbreviations
  • A valid ZIP+4 postal code
  • No commas or periods

While human errors are often why an address becomes invalid, they aren’t the sole culprits behind the challenges of maintaining accurate address data quality. 

Here are some underlying drivers contributing to the problem:

  • Data set decay: According to USPS, 17% of Americans change addresses annually, resulting in an average of 50,227 address change requests daily. Despite this number, only around 60% of movers inform the U.S. Postal Service, leading to outdated address data.
  • Poor data culture: Many frontline employees are unaware of their companies’ data quality challenges due to inadequate training or resources. The absence of investments in data management tools results in poor data quality maintenance. 
  • Merger and acquisitions: Data migration is common during mergers and acquisitions. Unfortunately, this process can introduce data errors as companies combine their operations, especially if a quality management structure isn’t in place.

When May Real Addresses Not Be Valid Ones?

Addresses appearing invalid in the USPS database can result from various factors. Understanding why an existing address might still be marked as invalid is essential. Here are common reasons for this discrepancy:

  • Non-existent addresses: One of the primary reasons an address is labeled invalid is its non-existence, which can happen if it becomes obsolete.

For instance, the address could’ve been a former business, or the street address information, such as the name or number, isn’t real.

  • Incorrect formatting: As mentioned, USPS-valid addresses follow a specific format. If an address is incorrectly spelled, improperly formatted, or has minor deviations like a wrong street name, it’ll lead to invalid status.
  • Unoccupied addresses: If an address is currently unoccupied, it may be marked as invalid since no resident can receive mail. Empty or abandoned properties are often considered invalid addresses until they have new occupants.
  • Non-registered addresses: The U.S. Postal Service classifies addresses that have not been verified or registered with its database as invalid. These cases usually occur when mailers relocate but fail to update their address information with USPS.

Guide to How USPS Address Validation Works

Understanding how USPS address validation works is crucial to maintaining accurate and standardized address data, which is significantly beneficial if you’re a business owner who wants to avoid undeliverable mail.

However, to fully grasp the inner workings of USPS address validation, you must first dive into its fundamental components.

NCOA and USPS CASS Address Validation

The National Change of Address (NCOA) is a record system. When you submit a change of address request to the Postal Service, your address information will be stored in this databank.

The stored address data will then be separated into individual components, such as the house number and street name, in a process called address parsing.

Afterward, USPS will standardize the address to meet its formatting guidelines, including adding missing details like the ZIP code and city name. This process utilizes the USPS Coding Accuracy Support System (CASS).

The CASS stage also involves checking the address against the USPS Locatable Address Conversion System (LACS). This system updates renamed or renumbered city-style addresses to match Postal Service standards.

An Example of What CASS Address Standardization Software Will Correct in an Address

To grasp the significance of USPS address validation, let’s assume you’re a business owner of an eCommerce retail store who wants to send a customer order to the following address:

1234 Seeside
Jasontown CA

Without the verification and standardization processes, USPS may return your mailpiece as “Undeliverable-as-Addressed” or UAA after failing to locate and ship the item, costing you valuable time, money, and a happy customer.

However, you can avoid these losses with USPS address validation. As mentioned, it’ll correct, standardize, and add missing address information. In this case, USPS’ NCOA and CASS processes will produce a deliverable address, such as the following:


In this example, the NCOA and CASS’s improvements to the provided address included amending the street name and adding the street suffix and the ZIP code.

Delivery Point Validation

The NCOA and CASS tools ensure that an address follows the U.S. Postal Service’s formatting guidelines. 

On the other hand, the Delivery Point Validation (DPV) system does the same job. However, it also determines if an address is eligible for delivery.

The DPV accomplishes this task by cross-referencing mailing addresses with the USPS database. If it finds a match, it will mark that address as valid. At the same time, the DPV system characterizes a mailing address as invalid and informs USPS that it’s undeliverable if there are no matching entries.


The Locatable Address Conversion System (LACS) is responsible for converting rural to city-style addresses. As mentioned, it’s also the system that amends renamed and renumbered city-style addresses. LACSLink is the database storing these corrected addresses. 

The primary function of LACSLink is to maintain up-to-date and standardized address data, which helps ensure addresses align with current postal standards and, by extension, enhance mail delivery efficiency.

CASS Errors and Warning Codes

Even when CASS confirms that a mailing address is valid, it may still adjust or add parts of the address. It will assign error or warning codes to the record in such instances.

Here are examples of CASS errors and warning codes:

  • dpv_status: This code indicates whether an address is validated, not validated, or not validated with required changes rejected.
  • dpv_type: This CASS code denotes the type of delivery point address. For instance, “H” means a highrise delivery point address, while “S” means a street address delivery point.
  • cass_errorno: This warning code signifies that an error occurred during CASS processing. For example, a “1.1” means that the address’ state wasn’t found. On the other hand, a “5.2” means the ZIP+4 code is unavailable.

Contact the U.S. Postal Service customer care center at 1-800-ASK-USPS (1-800-275-8777) for an exhaustive list of CASS errors and warning codes.

Alternatively, you can talk to a postal worker at your local post office. Visit to find your area’s nearest and most convenient USPS facilities.

CASS and NCOA Summary Reports

One of the most noteworthy advantages of USPS address validation is that it lets you access and export NCOA and CASS summary reports. These reports can provide valuable insight and documentation for your address validation efforts.

USPS Address Verification | Free Tools and Best Options

The United States Postal Service offers three tools to help you confirm a mailing address’ presence in the USPS database. These instruments include the following:

  • USPS Address Lookup: The USPS Address Lookup or “ZIP Code by Address” tool, as its name suggests, lets you check if an address is in the Postal Service’s address database.
  • Bulk USPS address validation: This verification tool allows you to validate several mailing addresses simultaneously, perfect if you’re a business owner who wants to maintain or improve your record’s data quality.
  • USPS address verification API: The USPS address API (application programming interface) and the Address Matching System API (AMS API) let you integrate USPS tools into your system to validate and standardize your addresses.

How to Validate an Address With the USPS Address Lookup Tool

Validating an address’ existence and deliverability using the U.S. Postal Service Address Lookup tool is straightforward. Here’s a step-by-step guide:

  1. Visit the USPS website at and head to the USPS Address Lookup tool page.
  2. Enter the details of the address you want to verify in the provided fields, including the company name, street address, house number, city, state, and ZIP code.
  3. Submit the request by clicking the “Find” button and wait for the validation results.
  4. Review the output to determine the deliverability and accuracy of an address.

Understanding the USPS Output

You can gain deeper insights into an address’ validity and its alignment with USPS standards by clicking on the “V” icon next to the address result of the USPS Address Lookup tool. Doing so reveals additional details about the address, such as whether it qualifies as a valid address point.

Here are the potential DPV confirmation indicator options:

  • Y: This indicator signifies that the address is valid and shippable. It’s the most precise address suitable for mail delivery.
  • D: The “D” indicator is also a positive sign, denoting that the building or house number is valid and deliverable. However, it also suggests that you didn’t enter the secondary number, such as a suite, apartment, or unit.
  • S: The “S” indicator suggests that the house or building number is valid. At the same time, it means that the secondary number has failed DPV confirmation. In other words, the address may not meet USPS standards for deliverability.
  • N: An “N” indicator means that the primary and secondary numbers have failed DPV confirmation. This address is likely not deliverable.
  • -: When the search results spit out a “-” indicator, it signifies that the provided address doesn’t match USPS’ records and is likely not deliverable.

If you require assistance using the USPS Address Lookup tool, call the Postal Service’s customer service hotline at 1-800-ASK-USPS (1-800-275-8777) or talk to a retail associate at your local post office. Visit to find post office locations near you.

Pros of Using the USPS Postal Address Verification Tool

Whether you’re an individual looking for smooth parcel handling or a business striving to fulfill customer orders, leveraging the USPS address verification tool presents various advantages.

The most significant of these benefits is it ensures smooth mail delivery. Streamlining your address data minimizes the risk of failed deliveries and returned mail.

If you’re a business owner, address verification can be beneficial, as it can enhance business operations and improve customer satisfaction, leading to reduced shipping costs and better returns.

Moreover, the USPS address validation tool is free, easily accessible, and user-friendly, allowing you to integrate it into your mailing operations seamlessly.

Six Cons of Using the USPS Postal Address Verification Tool

While the USPS address validation tool offers various advantages for individuals and businesses, its limitations may warrant considering third-party verification software.

Here are six disadvantages of relying on the Postal Service’s address verification tool:

Slow User Experience

Although the USPS Address Lookup tool allows you to validate addresses, it only allows you to do so one at a time. Using this tool can also be tedious, as you must divide an address into separate fields and navigate multiple pages to view the results.

These elements can be particularly disadvantageous for businesses, especially when verifying their address database with USPS’.

No Address Autocomplete

The USPS address verification tool doesn’t have an autocomplete feature. In short, it requires you to enter addresses manually whenever you want to validate one. 

Unfortunately, this process can introduce errors, such as typos or missing components. It also takes longer.

Missing 15 Million+ U.S. Addresses

The U.S. Postal Service’s database includes over 160 million domestic addresses. Unfortunately, this extensive databank doesn’t have the roughly 15 million non-postal addresses serviced by private mail carriers, such as FedEx(Federal Express) and UPS (United Parcel Service).

No International Data

The primary purpose of USPS is to provide reliable and affordable mail delivery services and tools to cater to the needs of the American people. 

Unfortunately, this dedication to domestic mailers means its address verification tool is unavailable for international addresses.

Lacking Useful Metadata

While the USPS address validator offers some metadata, such as ZIP codes, carrier routes, and vacancy status, it doesn’t provide other metadata points that can help expedite package processing and delivery, such as time zones and coordinates.

Strict Terms of Service (TOS)

The U.S. Postal Service levies strict terms and conditions on its address validation APIs. For instance, it prohibits using its address API to batch-validate a database. Violating these terms can result in the revocation of your access to the USPS address database.

For a more comprehensive dive into USPS’ address validation TOS, talk to a Postal Service representative by calling the customer care center’s phone number or visiting your local post office. Use to find the most convenient USPS facility among the over 31,000 nationwide. 

Here Is a Step-by-step Guide on How to Set Up Informed Delivery:

The USPS Informed Delivery service lets you get digital previews and manage mail heading to your address. Although this Postal Service feature is free, it’s only available to addresses with a mailbox with a USPS-assigned code in an eligible ZIP code location.

In other words, the U.S. Postal Service must validate your address to determine your eligibility for Informed Delivery. Fortunately, signing up for this USPS offering is straightforward.

Here’s a step-by-step guide:

  1. Visit the Informed Delivery page at and click the “Sign up for Free” button.
  2. Provide your address details so USPS can validate its deliverability and eligibility for Informed Delivery.
  3. Create an Informed Delivery account and finish the identity verification process. You can complete this stage using a one-time numeric passcode that will be sent to your phone number.
  4. Wait for the address verification and account activation, which can take three to seven business days.

If you can’t complete the mobile identity verification process, USPS offers in-person identity proofing services as an alternative at 18,000 locations nationwide. You can quickly find nearby post offices that provide this service by visiting

Informed Delivery – Change of Address

If you’re an Informed Delivery user and submit a COA request, you’ll stop receiving Informed Delivery notifications and lose access to your Informed Delivery® dashboard. You can resume using the USPS service and reap its benefits by verifying your address.

To accomplish this task, enter the validation code in the confirmation letter USPS will send at Note that you’ll receive two confirmation letters – one at your “old” address and another at your “new” address.

If you’ve finished relocating to your new home, use the validation code sent to this new address. If you haven’t moved, use the code USPS will send to your old address.

How to Cancel or Update Change-Of-Address Online

After you file a change-of-address request, the U.S. Postal Service will either email you a confirmation code or mail a letter containing one to your address. 

This code lets you track, modify, or cancel your COA order. Here’s how to do that:

  1. View, Update, or Cancel Your Change-of-Address

To start, visit the USPS change of address page. At the bottom of this page, you’ll find a banner. Click the red arrow next to it to begin editing your COA request. 

  1. Enter the Information Requested

After clicking the red arrow, you’ll be redirected to a new page. Here, you must provide your new ZIP code and the confirmation number, which is a 16-digit code.

Where to Find Your Confirmation Code

You can submit a COA request online or at the post office. If you choose the former, you’ll receive an email with the validation code. You can quickly find this email by searching the subject: “Your USPS Change of Address Confirmation.”

On the other hand, you’ll receive a confirmation letter at your new address through the mail. The confirmation code will be printed on the physical letter.

  1. Make the Necessary Changes

Once you’ve entered your confirmation code and ZIP code, you can now make various changes to your address change order, including the following:

  • Change your mail forwarding start date.
  • Adjust your mail forwarding end date.
  • Update your email address or phone number.
  • Switch from a temporary move to a permanent one.
  • Change from a family move to an individual move (though not from individual to family).
  • Cancel your address change order entirely.

How to Modify or Cancel Your Change-of-Address Request in Person

If you encounter issues with the online address change system, USPS provides an alternative option to update your COA request in person at your local post office. Fortunately, you can find your area’s nearest post office to resolve your problems using’s search tool.

UPS Address Validation

Like the U.S. Postal Service, UPS also offers an address validation tool to reduce returned mail rates, improve address database data quality, lower mailing costs, and enhance operational efficiency.

Frequently Asked Questions (FAQs)

1. When should I update my address?

If you want to ensure you receive your mail and packages at your new address, you must update the U.S. Postal Service before you move. USPS recommends at least two weeks, as its mail forwarding service can take that long to activate.

2. How do I correct my change of address?

If you want to make changes to your change of address request, such as correcting a typographical error, you can do so by visiting the USPS change of address page and clicking the arrow next to the“Want to View, Edit, Cancel, or Dispute your USPS Change-of-Address?” banner.

3. Where do I go to update, cancel, or modify my change of address request?

You can update, modify, or cancel your COA order online or at your local post office. You must provide your new ZIP and confirmation codes with the former option. On the other hand, you must present a valid I.D., such as a state-issued driver’s license, and evidence of residency, like a utility bill.

4. How much does it cost to change my address?

If you submit your change of address form online, you must pay a $1.10 identity verification fee. On the other hand, submitting your COA request at a post office is free.

5. Will changing my address with USPS update it everywhere else?

When you file a COA request, USPS will provide your new address to business mailers via mailer endorsements. However, a COA only updates your address with the Postal Service.

In other words, you must update your address manually with other entities, such as government agencies like the IRS (Internal Revenue Service) and private companies like banks and insurance providers.

6. How do I find my USPS validation code?

You can find your USPS validation code in the confirmation letter the U.S. Postal Service will send to your old and new addresses.

7. What is the USPS move validation letter?

To confirm your change of address order, the U.S. Postal Service will send a move validation letter (MVL) to the address you’re leaving or your old address, signaling that it received your request and must forward your mailpieces to your new address.

8. How do I verify my identity online for USPS Informed Delivery?

You must provide your mobile phone number to begin the online identity verification. USPS will then send you a one-time numeric passcode via text message. Enter this unique code, and you’ll be prompted with a confirmation page.

Note that if you encounter issues with the online verification system, you can complete the process in person at a USPS facility offering identity-proofing services. Visit to find the nearest post office that does.


  1. Informed Delivery® – Change of Address
  2. Guide to How USPS Address Validation Works
  3. How USPS® address validation works
  4. Checking the Accuracy of Your Address List
  6. What is USPS address validation and how it matters?
  7. NCOALink®
  8. Undeliverable-as-Addressed (UAA) Mail Statistics
  9. Delivery Address
  10. What Is LACSLink, And How Can It Help Verify Your Customer Address Database?
  11. USPS CASS Error Codes
  12. Contact USPS
  13. USPS® Address Verification
  14. USPS APIs
  15. Look Up a ZIP Code
  16. Informed Delivery by USPS
  17. How to Sign Up for Informed Delivery®
  18. USPS® In-Person Identity Proofing
  19. Standard Forward Mail & Change of Address
  20. How to Cancel or Update Your Change of Address
  21. How UPS Address Validation Helps Your eCommerce Business
  22. What is USPS address validation and how it matters?
  23. Change of Address – The Basics
  24. Mail Forwarding Options