P.O. Box Numbers


March 24, 2024

With the birth of the internet and instant messaging, you would think courier services like the U.S. Postal Service (USPS) would be on their way out. After all, fewer people are writing and sending correspondence through the mail.

But in an interesting turn of events, carriers are thriving, with USPS processing over 23.8 million packages daily- largely thanks to online retailers, such as eBay and Amazon, and online shopping.

Unfortunately, this increased traffic came with downsides. More mail toing and froing means more items can be stolen. According to a 2022 survey, roughly one in seven Americans fell victim to porch pirating, making security a significant concern.

Enter P.O. (post office) boxes— small compartments offering a secure and reliable means of receiving mail and packages. This article provides a comprehensive guide to P.O. boxes, including how they work, their benefits, and how to address a shipment to one using a P.O. box number.

Are you looking for additional information on post office box numbers? Talk to a Postal Service representative at your local post office. Visit FindPostOffice.org to find your area’s nearest facility quickly.

Shipping to P.O. Boxes: What You Need to Know

Shipping to P.O. boxes is common. However, it comes with unique guidelines and considerations. Understanding the P.O. box’s core concept is essential if you’re a business owner, online shopper, or simply someone who wants to ensure their mail and packages are safe and sound. 

Let’s break down the basics and explain the essentials, shall we?

What Is a P.O. Box?

At its core, a P.O. box, post office box, or postal box is a secure, lockable compartment located within a post office. Most of these containers use lock-and-key systems, with some older USPS facilities using combination locks.

You can rent these boxes from the U.S. Postal Service (USPS), as they offer an excellent alternative to using your home address for mail delivery. The primary purpose of P.O. boxes is to provide additional security, privacy, and flexibility for your deliveries.

What Is a P.O. Box Address?

A postal box allows you to direct incoming mailpieces away from your home or business address. It accomplishes this task by giving you an alternate delivery address — a P.O. box address.

What Is a P.O. Box Number Example?

Generally, P.O. boxes follow a specific addressing format, beginning with the words “PO Box” followed by the box number without punctuation. For example:

John Smith
PO Box 123
Anycity, USA 45678

That said, P.O. box numbers may sometimes appear as only digits without the “PO Box” prefix, such as “#910.” P.O. box address may also be abbreviated to “POB 112.”

Regardless, this formatting structure helps the Postal Service accurately deliver mail to the specific post office location and designated postal box.

How Many Digits Do P.O. Boxes Have?

P.O. box numbers usually consist of two to five digits, varying depending on the post office location.

Does the P.O. Box Number Go on Address Line 1 or 2?

When addressing mail to a P.O. box, the postal box number must go on the first address line. The second address line will be for the box’s city, state, and postal code.

Using our previous example, John Smith is the recipient. The first address line contains “PO Box 123,” as the mailpiece is intended to go to John’s postal box. Finally, the second address line, “Anycity, USA 45678,” is the target box’s city, state, and postal code.

How Does a P.O. Box Work?

Imagine a scenario where you won’t be available to receive a parcel at your regular delivery address, such as your home or office. If the mailpiece is a non-accountable item or doesn’t require a signature, USPS may leave it at the location, even without a recipient.

Unfortunately, you may expose your package to the elements or increase the likelihood of theft in these situations. The central premise of a P.O. box is to remove these risks by allowing you to receive your mail in a secure location that only you can access.

Can a P.O. Box Be a Legal Address?

P.O. boxes are ideal for receiving mail. However, they can’t serve as your legal business or home address. After all, a postal box address isn’t a physical street address, which companies and government agencies may require for lawful purposes.

Fortunately, the U.S. Postal Service provides premium P.O. boxes for that purpose. Unlike regular postal boxes, premium ones give the street address of the post office it’s located at, allowing you to receive deliveries from entities that require a physical address.

Why Do You Need a P.O. Box Address?

Postal boxes work functionally like traditional mailboxes, except the former isn’t in your front yard. With that being the case, why should you consider using one? Wouldn’t renting a P.O. box involve the hassle of visiting your local post office?

Here are some compelling reasons:

You Want to Maintain Your Privacy

If you value your privacy, a P.O. box is an excellent choice. It keeps your home or business address confidential, making it harder for unwanted individuals, such as identity thieves, to access your personal information.

You Send Direct Mail Campaigns

Direct mail campaigns can effectively raise brand awareness if you’re running a business. You can separate campaign responses from your regular business mail with a dedicated P.O. box, giving you a systematic way to manage correspondence.

You Want a Secure Mail Option

In an age of package theft and porch pirates, P.O. boxes offer a secure solution. These containers are within USPS premises and require a key or code to be opened, significantly reducing theft risk.

You Do Not Have Access to Your Mail

While today’s world is more interconnected than at any other point, some areas still have limited mail delivery services. If you’re unfortunate to be in one of these locations, having a P.O. box ensures you can receive deliveries.

Additional Benefits of Renting a P.O. Box

Apart from the abovementioned advantages, a P.O. box offers various other benefits. One of the most significant ones is flexibility. Most post offices provide round-the-clock access to their lockable compartments, allowing you to pick up your mail according to your schedule.

Additionally, shipments typically arrive faster at postal boxes. Instead of navigating complex neighborhoods looking for the correct residential or business address, which adds to the total delivery time, USPS can drop off your parcel at your P.O. box’s post office.

Other upsides to renting a P.O. box include allowing you to sign signature-required parcels digitally, forward mail between postal boxes, and rent USPS boxes out-of-state.

P.O. Box Size Options

When renting a USPS P.O. Box, you have various size choices to suit your needs. Here’s an overview of the available sizes and what they can accommodate:

Larger Packages for P.O. Boxes

P.O. box sizes range from extra small to extra large, with most having a depth of 14.75”. However, the maximum size for most USPS mailpieces is 108” in length and girth. In other words, you may receive a parcel that won’t fit in a postal box.

Fortunately, you have several options to receive a delivery, including the following:

  • Pick up from the counter: When your parcels are too large for a P.O. box, you’ll obtain a notice from your post office. This slip lets you claim overflow packages from the facility’s counter during business hours.
  • Secure parcel locker: Some post offices offer secure parcel lockers for oversized mail items. These lockers let you conveniently store and retrieve packages unsuitable for postal boxes at a time that best fits your schedule.

XS – Size 1

With a starting price of $4.67 a month, as of October 2023, extra small or size 1 P.O. boxes can be cost-effective if you need a dedicated mailing address for smaller mailpieces.

What Fits?

Extra small postal boxes are 3” by 5.5”, making them suitable for around 10 to 15 letters and three rolled magazines.

S – Size 2

Consider a small or size 2 USPS box for a slightly larger container. While this P.O. box costs marginally more, starting at $6 a month, it offers greater mail capacity.

What Fits?

Size 2 P.O. boxes measure 5” by 5.5”. They can accommodate over 15 letters, five rolled magazines, or a small Priority Mail Flat Rate box.

M – Size 3

Expect a starting price of $9 monthly for a size 3 or medium postal box. Consider choosing this P.O. box size option if you prefer your mailpieces without creases or folds.

What Fits?

Medium-sized USPS boxes are 5.5” by 11”, offering space for large envelopes, stacks of magazines, and even two small Priority Mail Flat Rate boxes.

L – Size 4

If you require a lockable compartment that can hold a significant amount of mailpieces and prevent damage, consider a large or size 4 P.O. box. The starting monthly rate for this box is $13.33.

What Fits?

Large P.O. boxes, measuring 11″ x 11″, provide room for small and medium Priority Mail Flat Rate boxes while still having ample space to cater to an additional 10 to 15 letters.

XL – Size 5

Size 5 or extra-large postal boxes provide the most space, making them considerable options for receiving high-volume mail and packages frequently. The starting monthly price to rent one is $23.67.

What Fits?

Extra-large boxes measure 12″ x 22.5″. They’re ideal if you expect multiple shipments of varying sizes, as they can hold several packages simultaneously.

“I Would Like to Open a P.O. Box. What Are the Steps?”

Whether you need a secure container for personal or business use, getting a P.O. box is straightforward. Here are ways to apply for a postal box service and some considerations you must remember:


To open a postal box online, follow these steps:

  1. Visit the U.S. Postal Service at USPS.com and navigate to the P.O. Box section.
  2. Search for an available P.O. box by providing your physical address, city, state, or ZIP Code in the “Find a P.O. Box Near You” field.
  3. Select your desired post office location.
  4. Choose a postal box size appropriate for your needs and your preferred rental term.
  5. Fill out the P.O. box online application form (PS Form 1093) and agree to the terms and conditions.
  6. Provide payment information and select the preferred payment method.
  7. Print and submit your P.O. box application to your selected post office location, along with two photo IDs, such as a state-issued driver’s license and a U.S. passport.

You must bring the printed 1093 form and proof of identification within 30 days of your online application. You’ll receive your P.O. box keys once the Postal Service validates your identity.


If you prefer the in-person approach, here are the steps you must follow:

  1. Print a copy of PS Form 1093 and complete all the required information.
  2. Visit FindPostOffice.org to find your area’s post office locations, and bring a copy of the completed form and two acceptable forms of identification to your chosen USPS facility.

Choosing the Size of a P.O. Box

The box size must depend on the volume of mail and packages you anticipate receiving. To ensure you select the appropriate postal box size, you must assess your mailing needs carefully. Remember, P.O. boxes come with fees.

Selection of a P.O. Box Rental Price

Speaking of fees, the price for renting a P.O. box depends on its size and ZIP code, which is based on whether it’s market-dominant or competitive. Generally, larger compartments in bigger cities are more expensive.

For instance, a size 5 box belonging to USPS’ market-dominant fee group 1 costs $319 quarterly as of October 2023. At the same time, an extra small postal box in USPS’ competitive C44 fee group is $39 per 3 months.

For a comprehensive look at your potential postbox costs, visit your local post office. Use FindPostOffice.org’s USPS facility finder tool to locate your area’s most convenient post office locations.

“What Address Should I Use for My Business?”

It may be challenging to portray a professional image using a residential address as your business address. Fortunately, if you’re a small business owner, a postal box may be the answer you’re looking for.

Renting a P.O. box gives you a separate delivery address, allowing you to draw a line between your personal and business affairs. As mentioned, it also protects your privacy and information while giving you a commercial address that some organizations, such as banks, may require.

Can You Get a P.O. Box Without a Physical Address?

Although you can use a P.O. box as an alternative mailing address, you must have a physical address, whether residential or commercial, to rent one. In other words, you cannot get a postal box without a physical address.

“How Do I Get a Physical Address From a P.O. Box?”

As mentioned, while standard P.O. boxes don’t provide a physical address, premium ones do via USPS’ street addressing service. This service allows you to use your postal box’s post office as the physical address.

“What if the P.O. Box I Want Is Not Available?”

When you apply for a postal box service, you can choose its size and location. However, your desired P.O. box may sometimes be unavailable. In such a situation, you can select a different-sized compartment, apply for one at a different post office location, or ask USPS to add you to the waitlist.

If you select the final option, the U.S. Postal Service will contact you through email or phone when your preferred P.O. box becomes available. Note that you only have two days to reserve the compartment. Otherwise, USPS will offer it to the next person on the waiting list.

“Can I Get a P.O. Box in a Different City or State?”

One of the many benefits of applying for a USPS P.O. Box is that you can rent one in a different city or state. This feature is significantly beneficial if you’re a business owner trying to increase your brand’s reach.

Unfortunately, while you can apply for an out-of-city or state postal box service online, the U.S. Postal Service requires you to bring your printed application form and proof of identification to the post office where your chosen P.O. box is located.

Sending Mail to a P.O. Box vs. Street Address

How you address your mail or packages can be the difference between successful deliveries and USPS returning your shipments. Remember, while a P.O. box is a viable mailing address, it’s distinct from a street address.

How to Determine if an Address Is a P.O. Box

To determine if an address is a P.O. box, look for the recognizable P.O. box number, often represented as “P.O. box ###” or “POB ###” format. On the other hand, street addresses will generally include the street name and number.

For instance:

P.O. Box AddressStreet Address
PO Box 123456 Main St.

Why Identify Whether an Address Is a P.O. Box or Not?

Correctly identifying the address format ensures that the mail and packages you send arrive at their intended destination safely and on time. Moreover, doing so also determines whether you can use a specific mail service.

Couriers like FedEx (Federal Express) and UPS (United Parcel Service) have different delivery protocols and won’t ship to USPS boxes. The exceptions to this rule are if you use FedEx SmartPost or UPS SurePost or if the recipient has a premium P.O. box with a street address.

Writing Both the P.O. Box and the Street Address on the First Address Line

As cited, the P.O. box number usually goes in the first address line. But what if you provide the box identifier and the street address in address line number 1? Generally, USPS will use the postal box address as the mailing address due to the cheaper shipping cost.

What Happens When You Write an Invalid and a Valid Address on Different Address Lines?

You can include the P.O. box number and the street address in the package. Doing so can help ensure your mail will still reach its intended destination even if one address is invalid.

Therefore, it’s best to separate the postal box number and the street address into different lines. Better yet, use USPS’ address verification tool, which corrects mailing address formatting to match USPS standards and verifies its validity.

What to Do Once You Have Signed Up for a P.O. Box Address

Once you’ve secured a postal box, you must ensure you use it as your new address. In other words, provide your new PO box number to your mailers. Otherwise, you’ll continue to receive mailpieces at your old address.

However, if you want to use your P.O. box as your permanent mailing address, you must submit a change of address (COA) request (PS Form 3575) with USPS. Fortunately, the Postal Service allows you to do so online or in person.

Note that a COA request only changes your mailing address with USPS. In short, you must still update other entities, such as government agencies, financial institutions, and utility providers, to direct their mail to your P.O. box.

How to Find Out a P.O. Box Number

Whether you need to provide your P.O. box number to a mailer or send a mailpiece to a postal box, there are various ways to locate these lockable containers’ identifiers.

Your Own Mailbox

If you misplaced or need help remembering your P.O. box number, your best bet is to contact USPS. Call its customer service hotline at 1-800-ASK-USPS (1-800-275-8777) or visit your box’s post office. Either way, the U.S. Postal Service will require you to verify your identity.

Individual’s Mailbox

USPS typically doesn’t disclose P.O. box addresses without the owners’ permission. Therefore, you must ask for the box number if you’re trying to address a letter or package to someone else’s P.O. box.

Check their personal websites or social media accounts if you can’t reach them. Conversely, you can call 411 Directory Assistance or use the database of a people finder service.

Business Mailbox

Businesses usually publicly provide their P.O. box number on their website’s “Contact Us” page. If a business’ postal box information isn’t listed, inquire about it through the company’s contact number or email.

Mailboxes at the Post Office

As mentioned, the “P.O.” in P.O. boxes stands for “Post Office.” As such, it makes sense that the U.S. Postal Service is the primary provider of these postal boxes. However, private companies, such as UPS, also provide mailboxes.

That said, if you believe your intended recipient has a USPS box, you may be able to request the container’s number by submitting a Freedom of Information Act (FOIA) appeal to the corresponding post office’s postmaster.

Note that it may take up to 20 business days to receive a resolution from USPS. Additionally, as cited, the Postal Service may not disclose the information you’re seeking if they don’t obtain permission from the owner.

It’s best to talk to a Postal Service representative via USPS’ customer care center or post office in these situations. Visit FindPostOffice.org to find a specific post office out of the 31,000 nationwide.

Why Do Organizations Provide a Street Address and a P.O. Box Address?

Businesses are often guilty of using both the recipient’s P.O. box and street address when sending a mailpiece. Organizations do this primarily to cover all their bases, ensuring USPS delivers their parcels successfully.

Sending Mail Through USPS to a Physical Address Over a P.O. Box Address

Providing your recipient’s street and postal box addresses as the primary and alternate mailing addresses gives USPS options. For example, if the intended receiver isn’t available at the street address, the Postal Service can drop off the mail item at the supplied P.O. box address.

Delivery of Mail by USPS to a P.O. Box Address Instead of a Physical Address

If you want the U.S. Postal Service to prioritize delivery to a postal box, write the P.O. box address on the first address line and use the recipient’s street address as the alternative mailing location.


Although USPS provides free P.O. boxes in particular circumstances, renting a postal box involves fees. Let’s break down the payment aspect of getting a P.O. box.

How Can I Find Out How Much a P.O. Box Will Cost?

USPS provides clear pricing information on its website, so you can quickly determine the cost of renting a P.O. Box based on size and location. Conversely, you can visit your local post office and inquire in person. Visit FindPostOffice.org to find your area’s nearest USPS facilities.

What Options Do I Have for Making a Payment on My P.O. Box?

The U.S. Postal Service provides four convenient options to pay for the P.O. Box service. These choices include the following:

  • Online Payment: You can use a debit or credit card to make a postal box payment. Visit the P.O. Box application page, click “Renew” to access the “Manage P.O. Box” page, and select “Renew P.O. Box” for a one-time payment.

Note that this option is only available 30 days before your next due payment.

  • In-person payment: Pay via a self-service kiosk (SSK) or at a post office. Make this process more straightforward using FindPostOffice.org’s USPS facility finder tool to locate your nearest post office.
  • Payment by mail: USPS allows you to send a check or money order payable to your P.O. box’s post office location’s postmaster to cover your box’s rental fees. If you’re paying with a check, include your P.O. box number on the memo line.

How Frequently Do I Have to Pay for My P.O. Box?

The frequency of payments depends on your rental term. When applying for a postal box service, you can choose between 3-, 6-, or 12-month terms. However, if you select a 3-month rental period, you’ll automatically be enrolled for renewal with no opt-out.

Can I Renew My P.O. Box Online, or Do I Have to Do It in Person?

You can renew your P.O. box rental online through the USPS website or at your local post office. Online renewal offers more convenience, while in-person renewals can provide personal assistance. Ultimately, the appropriate choice depends on what you value more.

When Do I Need to Pay My P.O. Box Account Renewal Fee?

To keep your P.O. box active, submit your payments by the 10th of the due month. Otherwise, the U.S. Postal Service will close your P.O. box on the 11th of the due month.

Are P.O. Box Rental Fees Eligible for a Refund?

If you no longer require P.O. Box services and decide to close it before your 6- or 12-month rental term ends, you may be eligible for a partial refund.

The amount USPS will reimburse depends on when in the rental period you cancel. Here’s a quick look at the U.S. Postal Service’s P.O. Box refund policy:

6-Month Rental Term12-Month Rental Term
50% refund if you cancel within the first three months75% refund if you cancel within the first three months
No refund after the beginning of the fourth month50% refund if you cancel between the term’s fourth and sixth month
25% refund if you cancel between the term’s seventh and ninth month
No refund after the beginning of the 10th month

Access and Services for Your P.O. Box

What happens once you’ve opened a P.O. Box? Here’s what you need to know about accessing your box and the services available.

I Recently Opened a P.O. Box. How Do I Get My P.O. Box Number and the Keys for My Box?

After successfully applying for a P.O. Box, paying the rental fee, and being notified that USPS has verified your identity, you’ll receive your postal box number and keys. If you need additional keys beyond the first two, you must pay a $12 surcharge.

Can I Access My P.O. Box Any Time of the Day?

Many post offices offer 24/7 access to their P.O. box lobbies. However, the business hours can vary based on the specific post office location. To determine if your local post office provides round-the-clock postal box access, visit its location, which you can find with FindPostOffice.org.

As a Small Business Owner, Are There Any Additional Services I Can Get With My P.O. Box?

As a small business owner, you can explore additional services for your P.O. box. One of these add-ons is caller service, which tasks the U.S. Postal Service to hold your overflow mail until you can pick it up.

Talk to a Postal Service representative at your local post office for more information on USPS services that can benefit your business. Visit FindPostOffice.org to find your area’s nearest USPS facilities.

Can You Change A USPS Business Account to a Personal Account or Vice-Versa?

USPS understands the changing needs of customers. As such, it allows you to convert your personal account into a business account through your USPS.com account settings.

Unfortunately, the reverse isn’t possible. You cannot change a business account to a personal one. Fortunately, creating a USPS.com account is free, allowing you to easily create a separate personal account.

How Do I Manage My P.O. Box Account Online?

The USPS website lets you make payments, update your account information, and access additional services. To do so, visit the “Manage P.O. box” page and sign in.

What Is Street Addressing and How Can I Get It for My P.O. Box?

Street addressing is an add-on service that allows private carriers like FedEx and UPS to deliver to your premium postal box, bridging the gap between a P.O. box and a physical street address.

How Do I Close a P.O. Box if I Move?

If you need to close your P.O. Box due to relocation, click the “Close/Request Refund” option next to your active postal box on the “Manage P.O. Box” page. Alternatively, you can request rental termination at your P.O. box’s post office.

Can I Receive Signature-Required Items in My P.O. Box?

When you apply for a P.O. Box, the U.S. Postal Service will allow you to store your signature digitally. If your signature is on file, you can receive items that require a signature in your lockable container.

Fact Sheet: Locate a Post Office Box

For your convenience, the Postal Service now lets you search for available P.O. boxes online, eliminating the need to contact its customer service hotline or visit a local USPS facility.

Here are the steps to get a list of available postal boxes based on your ZIP code or address:

  1. Visit USPS.com/POboxes.
  2. Click “Go” under the “Locate a Post Office box” section on the right.
  3. Enter your ZIP code or physical address.

Sending Mail to a P.O. Box via UPS and FedEx

As mentioned, courier services like FedEx and UPS typically don’t ship to USPS boxes. However, the keyword here is “typically.”

How to Get UPS and FedEx to Deliver to a P.O. Box

Some FedEx and UPS delivery services, such as FedEx SmartPost or UPS SurePost, allow you to mail to postal boxes. These options are U.S. Postal Service collaborations that utilize the USPS network.

Alternatively, you can subscribe to USPS’ street addressing service. It lets you use your P.O. box’s post office as a physical mailing address and receive packages from other carriers.

The Trouble With Traditional P.O. Box Addresses

While using a P.O. box address as a mailing address offers security and privacy, it has limitations. For one, postal boxes make changing your address challenging, especially considering that you may not get a refund if you’re late into your rental term.

However, the most noteworthy downside of using a P.O. box address is that it’s tied to the post office. In other words, your incoming mailpieces will head to your postal box, forcing you to visit the facility it’s in whenever you have letters or packages.

Making the Most of Your P.O. Box

Getting a postal box costs money. Unfortunately, the more competitive your location is and the bigger the compartment you need, the more expensive renting one becomes.

Therefore, you must maximize your P.O. box. To do so, you can consider additional services like Informed Delivery, which gives you a digital preview of what’s heading to your lockable container.

You can also opt for street addressing, allowing you to receive not only mailpieces shipped through the U.S. Postal Service, but also from other carriers, including FedEx, UPS, DHL (Dalsey, Hillblom, and Lynn), and Amazon.

Alternatives to P.O. Boxes

While P.O. boxes offer significant advantages, they might not be the perfect fit for everyone. Explore alternative options that provide similar benefits, such as virtual mailboxes and private mailbox services offered by shipping stores like the UPS Store.

For additional options, talk to a Postal Service representative by calling 1-800-ASK-USPS (1-800-275-8777) or visiting a local post office. Remove the guesswork from finding USPS facilities by using FindPostOffice.org’s post office locator tool.


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  4. PO Box™ – The Basics
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  6. PO Box vs. Street Address: Delivering Postal Mail via USPS
  7. How can I identify whether or not an address is a P.O. box?
  8. How to Write Address & Mail to a PO Box for Business
  9. PO Box Address Format
  10. Redelivery – The Basics
  11. Premium PO Box Service Street Addressing
  12. Direct Mail: What it is, How it Works, In Practice
  13. Service Not Available: USPS Mail Delivery is More Limited Than You May Think
  14. Minimum and Maximum Sizes
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  16. USPS Price List
  17. Can I ship via FedEx or UPS to a PO box?
  18. USPS® Address Verification | Free Tools and Best Options
  19. Change of Address – The Basics
  20. Standard Forward Mail & Change of Address
  21. Contact USPS
  22. How to Pick Up Mail at the U.S. Post Office
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  24. FedEx Ground® Economy shipping
  25. UPS SurePost®
  26. Informed Delivery by USPS