USPS Insufficient Address Mail – How to Fix It

Businessman looking at rejected mail

A USPS Insufficient Address alert is typically printed on a yellow sticker affixed to returned mail. It indicates that the mailpiece is Undeliverable As Addressed (UAA).

Insufficient address usually means a vital address component is missing or illegible, such as a building number, suite, apartment, unit, street name, etc.

Smarty™ has address validation tools that help businesses reduce returned mail and the associated shipping cost by formatting the address to the USPS standards and telling you whether the address is complete and valid before mailing.

Handling insufficient addresses is essential to avoid wasted time, money, and potential customer dissatisfaction.

Try them out here, or continue below for more information about the Insufficient Address message issued by USPS.

Single Address Validation Bulk Address Validation Address Validation API

Let's peek at what we'll be addressing (see what we did there?):

What Does USPS Insufficient Address Mean?

Returned mail from the post office comes with a yellow label with "Nixie" printed in the top left corner. The term is derived from the 20th century USPS role of "Nixie clerk" who was responsible for determining what to do with undeliverable items. Today, these labels are referred to as Undeliverable As Addressed (UAA).

The "insufficient address" USPS endorsement is one of the most common returned mail messages that the postal service provides, telling the sender why the mail was returned without being delivered.

Golden compass on sandy ground

When mail is marked as "return to sender" and returned as "insufficient address," it's because the parcel or envelope is missing crucial address details - such as:

  • An inaccurate ZIP Code
  • Missing address directionals, like N, S, E, W
  • An incomplete city name
  • A misspelled street name
  • A missing street number
  • Invalid postal abbreviations for states, streets, or cities
  • Or, among the most common, a missing secondary address, like apartment, unit, or suite number

Fortunately, running a mailing address through a USPS address validation service like Smarty's, helps you identify and fix USPS insufficient addresses prior to mailing and before they have the chance to become returned mail. Insufficient addresses are easily fixed, once you know the problem, but it's not the only thing that can trigger a UAA tag.

More Reasons USPS Marks My Address As UAA

There are several reasons that your mail is being marked as undeliverable as addressed due to invalid, insufficient, or incomplete addresses, including missing forwarding information, missing secondary information, and/or insufficient postage.

  • Missing Forwarding Information means that your recipient forgot to set up a forwarding address when they moved. The current resident your company sent the mail item to doesn't want the magazine subscription, bank statements, or credit card pre-approvals that you intended to go to Grandma LouLou, but they don't know where she moved to, and neither does the mail carrier, so it gets sent back to you with that pesky, little "UAA" label attached.
  • Missing Secondary Information typically refers to an apartment number, suite number, etc. that is either invalid or is missing entirely. These may be marked as insufficient, but might also be marked as a USPS incomplete address or incorrect address; this ranks among the most common returned mail reasons.

    While the package label might include the correct address, if the secondary address is missing, the package might only make it to the correct apartment or business complex. You can bet that the mail carrier isn't about to go knocking on doors to track down the intended recipient and dropping it off in the lobby could result in a lost or stolen package. So, back it goes to the post office and then back to your return address!

    You should be aware that if you hand-write the deliverable address onto the mail item unless you got straight A's in the 3rd grade for your handwriting legibility, this could also be flagged as USPS Insufficient Address. If they can't read it, they can't deliver it to the correct location. Don't write like a doctor - take your time, use clear capital letters, or ask a friend for help if needs be.

    Also, be aware that ink smudges. If you write the address by hand or use an inkjet printer, it only takes a little friction to smudge the ink, making the address illegible. Water from rain could also potentially cause smudging. Use a laserjet printer instead to make your labels non-smudgeable, or you can place clear tape over a handwritten or inkjet-printed address for the same effect.

  • Insufficient Postage usually means that the sender miscounted the amount of stamps required to ship the package or envelope. Without the correct amount being paid to deliver, the mail service might not even make it past its first stop before being sent right back to the sender using the return address they provided.

Mail can also be returned to sender because the address is vacant, the addressee isn't known at the place of delivery, the mailbox was too full or inaccessible during a delivery attempt, the label is damaged or smudged, the address isn't formatted correctly, the business is closed, the home or business is new construction and hasn't been added to the USPS database yet, or the address is just plain bad.

What Happens to Envelopes and Packages with an Insufficient Address USPS?

Message lost in a bottle

As was mentioned earlier, USPS Insufficient Addresses are typically returned to the sender. However, this can become more than just a small nuisance, especially when dealing with shipping to your customers. A lot of waste is happening behind the scenes.

Let's take a minute to address (ok, ok we'll stop) all of the other obstacles that could - and often do - accompany insufficient and USPS incomplete address labels:

  • Time Wasted - Did you know that you won't typically get the alert that your package or mail is considered "insufficient address" until the final leg of the journey? Not only is this a very strong likelihood, but sometimes the undelivered package may not even be rerouted to you immediately, but rather have a major delay.

    More often than not, the destination post office will hold onto your customer's mail for up to 15 days until they come to claim it in person. If they're off vacationing in a sunnier climate, they may not be able to reach your item/s in that time frame, and it'll be marked as "unclaimed."

    Now imagine that your company is shipping 5,000 mail pieces per week and 5% of them come back as insufficient. How much time is your organization wasting to fix the errors? How much time are you wasting waiting for those items to arrive, only to find them returned to your business a week later?

  • Money Wasted - Not only did you waste labor hours, but you are also paying to send and resend the package. You now have to pay the cost of shipping to send the mail item again once you correct the insufficient address.

    Let's also think about the additional manpower required to track down those parcels. The time it takes to fix these undeliverable address issues could add up to hundreds of labor hours per year, if not more.

    Still not convinced? According to a 2015 survey, UAA mail (or Undeliverable as Addressed, including USPS Insufficient Address) cost both the Postal Service and its customers - about $1.5 billion a year alone, and an excess of a whopping $20 billion for the whole mailing industry. How much money is your company losing in this grand scheme?

  • Product Wasted - Sometimes, a package might not be handled with as much care as you would've hoped. Items can be lost while going through this ferris wheel of sending and returning, and technically postal workers aren't allowed to put back an item if they aren't 100% sure it came from the package.

    You may get only part of the package back. This goes into the money wasted category technically, because now you have to remake or repurchase the items to complete the package, or lose out on the sale completely and refund the customer because you no longer have access to additional parts. And, what is happening while you are figuring all of this out? That's right, you are wasting more time, aka money.

  • Frustrated customer
  • Customer's Patience Wasted - This might go without saying since we have likely all been on the receiving end of an insufficient address error, but from the customer perspective, we're peeved.

    When you order something, you are ordering it typically with a deadline you are trying to meet. Maybe you need your Princess Leia costume to arrive in time to win the upcoming company Halloween party. Good luck with that when you check your tracking information only to find out that your package was undeliverable or marked as an insufficient postal address. (Looks like that company needs to use Smarty for their ordering platform.)

    As a customer, what are you going to do? That's right. You'll blow up their customer service lines, email them, and waste a ton of their time trying to contact anyone, preferably a human to help you track it down. You may even scrap from buying from that company ever again, and then go give your business to another competitor who will deliver your stuff.

Insufficient Addresses & USPS Marketing Mail

USPS Marketing Mail (also known as Standard Mail or Bulk Mail) is a mail class offered by the United States Postal Service (USPS) designed for businesses and organizations to send promotional and advertising materials in bulk quantities, such as catalogs, postcards, flyers, and advertising mail.

By presorting and preparing mail in large quantities, businesses can qualify for discounted postage rates.

Unlike First-Class Mail, Marketing Mail isn't forwarded or returned automatically when marked as UAA. So, bulk mailers may not be aware that their mailers aren't being delivered to every intended recipient. Mailers can pay an additional fee and add a "Return to Sender" endorsement.

You may not want to add the endorsement with every mailing, but adding it periodically can help you to evaluate how often your organization's Marketing Mail is being delivered successfully.

High-quality USPS CASS Certified address validation can also help your company scrub mailing lists and minimize all forms of UAA mail, giving you a squeaky-clean list of accurate addresses.

Fixing Insufficient Address USPS Using Redelivery

Well, the short answer is to be proactive. Make sure the address is correct from the beginning, meaning that you are using the correct postal address format for USPS. The USPS defines a standardized street address as

"one that is fully spelled out, abbreviated by using the Postal Service standard address abbreviations... or as shown in the current Postal Service ZIP+4 suffix file."

Can we put that in plain English please? Yes, yes we can.

Here's the correct USPS street address format you must follow in layman terms:

Putting a letter in the mailbox
  • Name of the recipient
  • House or building number
  • The route or road with associated North, East, South, or West if necessary
  • The city
  • The state's two-letter abbreviation
  • A ZIP Code (sometimes this means a complete ZIP Code with the mail delivery route indicating numbers that follow)

"Ok, but I've used the correct address format and double-checked the recipient's current address, SO WHY AM I STILL GETTING THIS ERROR?" you may be shouting at the computer. Good question, and you aren't alone in feeling the frustration here.

The piece many people and companies are missing is address validation in combination with address standardization.

As we mentioned in more detail in a previous article, "Address Standardization is the process of converting an address into a standardized, consistent format of the local postal authority, such as the USPS for US addresses."

Yes, you could do this manually, but we at Smarty know that the right software can be faster and more accurate than any team of humans. That's why we built the tools to do so. It's definitely a better option than hiring an entire team to manually sift through and correct addresses.

Ok, so the address has been standardized, meaning that the post office should accept it, right? Well, not always. That's why you need the address validation as well.

Address Validation is what makes sure that a correctly formatted address is also a valid address. If you were to put an address on your parcel like this, an address standardization tool would show that it's formatted correctly:

11395 W. Dunnellon Rd,

Crystal River, FL 34428

And, it is! There's just one major problem . . . that house (11395) number doesn't exist on W. Dunellon Rd! Without address validation, that package will likely make it all the way to Florida before the postal carrier realizes that the delivery address isn't valid and ships it back. Looks like Leia will have to be a last-minute DIY costume instead.

Let's minimize every time-wasting, money-eating insufficient address & UAA notice we can!

Fixing & Avoiding USPS Insufficient Address with Validation

Someone fixing a kitchen sink

Smarty has address validation tools that help businesses cut cost of shipping, reduce waste, and increase revenue. Smarty will flag addresses that are missing secondary information, but it will not mark it as non-deliverable, making sure that your packages arrive safely and on time.

We source our addresses from multiple public & private datasets, making our validation software even more complete as new businesses and homes are built. Also, integrating Smarty's suite of APIs is easy since we provide SDKs and tons of sample code for many popular languages, from .NET to Ruby. You can also use the USPS Address Validation API, but it has limitations.

Our APIs are intuitive enough to be seamlessly integrated into your systems within hours. No need to reinvent the wheel here; let's just make what you already have be that much better.

Here are products we offer to help with fixing insufficient address messages and prevent things from getting mailed to the wrong address, before they become a problem:

Smarty's APIs can be integrated into any system to make address validation automatic in any business process. It can be used for USPS, FedEx, DHL and UPS address validation along with any other shipper. We're so nice that we'll even let you use it for free.

What If My Tracking Update Says Insufficient Address?

Warehouse worker tracking packages

When you encounter the 'insufficient address' notification on a tracking update for your USPS package, your initial step should be to get in touch with the Post Office ASAP.

Verify whether the facility has already initiated the process of returning the items to you. If you catch the process early enough, you can give them the correct address and request them to resume the delivery.

A UAA message is triggered as soon as a postal worker identifies your address as incomplete. However, it can take hours or even days for the return process to commence. This is your window of opportunity to take action.

The shipper or the recipient may be able to claim the parcel from a local post office. Just ask the USPS to hold onto your packages for a few days. If no one claims the item within the specified time frame, the Post Office may discard it or return it to the sender.

If, you haven't received your package within seven days from the posting date, here are your top 3 options:

  1. Go to USPS's Find Missing Mail page and submit a Help Request Form, or Submit a Missing Mail Search Request.
  2. Call the USPS support line at 1-800-275-8777 to connect with a Consumer Affairs rep. They'll assist you with packages marked as "insufficient address" and similar UAA endorsements. (Be prepared to be on hold for a while.)
  3. Visit a nearby Post office and file a Missing Mail Search Request there.


Getting USPS Insufficient Address labels from the post office is a frustrating issue that many people deal with in their personal lives and in their business spheres. However, it's mainly a preventable issue.

Using Smarty's software, you can standardize, validate, and de-duplicate your mailing lists with the click of a button, making those taxing insufficient address labels a thing of the past.

Start using our software today and ensure that you can win that Halloween competition and meet your quarterly goals this year, and for many more to come.

Ready to get started?