To address a mail item or parcel to a PO box, write the recipient's first and last name on the first address line, with the company or organization name right below it. Then, write “PO box” followed by the PO box number (2-5 digits) on the next line. Avoid using any punctuation. Finally, on the last line, write the ZIP code, city, and state.

If you see that the PO box number has a designation like BIN or CALLER, leave it out when writing the address on the envelope. Write your return address in the upper left-hand corner of the package or envelope. As a business, always include your return address on the mail you send. This lets the recipient know who you are and ensures that the mail can be returned to you if it's undeliverable.

The United States Postal Service (USPS) depends on automated Optical Character Recognition (OCR) sorting machines to process mail. So, incorrect formatting or unnecessary punctuation in your address block will lead to rejections. This guide is the perfect place to learn the USPS-compliant rules to address business mail to a P.O. Box.

TL;DR

• To address mail to a P.O. Box, include the recipient's name on the first line, followed by “P.O. Box” and the number, then the city, state, and ZIP code.
• Always include a return address in the upper left corner to ensure mail can be returned if undeliverable.
• Avoid using punctuation in the address to streamline processing by USPS.
• Businesses often use P.O. Boxes for privacy, security, and efficiency, especially startups and online companies.

There are a couple of things that you should know about before filling out the address or providing the contact information needed for the postal mail, like certified mail sent to a P.O. Box. Below, we discuss the steps you need to take before sending out a postal mail to businesses or individuals who rent a P.O. Box.

Step 1: Write the Recipient’s Address in the Middle

According to the USPS Publication 28 (Postal Addressing Standards), the recipient’s address must be written in the center of an envelope or shipping label. Besides, mail going to a business P.O. Box should have a left-aligned, four-line format. Also, USPS recommends writing the address in uppercase letters for better readability. Here’s a step-by-step breakdown of how to address mail to a P.O. Box business address; 

1. Line 1: Use this line to write the recipient or department name. Place this line at the top if you are sending the mail to a specific employee or department.
2. Line 2: Mention the business’s officially recognized name below the recipient’s name. 
3. Line 3: Write “P.O. Box” and the specific two to five-digit number. Always avoid using punctuation marks while writing this line. For instance, USPS will prefer “P.O. Box 1234” over “P.O. Box 1234.” 
4. Line 4: Now you have to include the city, state, and ZIP code of the destination. Use the two-letter state abbreviation and ZIP code (ZIP+4 codes are preferable). There should be a single space between the city and the state, and double spaces after the state abbreviation. 

Standard Business P.O. Box Example: 

If you are writing the address and notice that the PO box number is written with a designation, like BIN, CALLER, and more, omit such edits immediately on the envelope. For instance:

• Instead of writing BIN M
• Always Write PO BOX M when addressing an outgoing letter or even a mail

 Also Read: How To Use CO In Mailing Address

Step 2: Provide the Return Address

Your postal mail's return address must be written on the upper left-hand corner of the package or cover. As a business or corporate company, you must always include the return address on the postal mails you send out because it informs the addressee about who you (the sender) are and because to get the mails back if the mail goes undelivered. This is important because this gives you valuable insight into the postal address database of your company.

 Also Read: How to Return Mail to Sender?

The postal address database of a company can be filtered using an advanced address verification tool like PostGrid that offers deliverability of a whopping 99.99% through the wide network of trusted delivery partners across the USA.

However, this is not always the case because sometimes, despite the system's accuracy, there may still be cases of undelivered postal mails, and the return addresses allow you to get a comprehensive idea of this data and may even help you reestablish your relationship with the customer.

Step 3: Affix A Valid Stamp

Add a stamp or even a prepaid shipping label at the upper corner to the right to cover the delivery costs. Try to make sure that the postal stamp is not overlap the address or any other information related to the delivery. You can use the USPS Postage Calculator to add up the cost of your letters or even ask the post office for further assistance.

Additionally, you might need to submit additional postage charges or fill out a few customs forms when planning to send direct mail internationally. Also, you can submit these forms online before shipping when planning how to address a letter to a PO Box.

Step 4: Double-check the Address

The next step involved in writing a PO box address is double-checking the address that you have written on the postal package or cover. Although this may sound like a no-brainer, you will be surprised how many companies make the mistake of ignoring this step. It is arguably the most commonly made mistake by businesses/companies that use advanced address verification tools because they often rule out the possibility of an undeliverable address altogether.

Even if the address verification service is completely accurate, you must not ignore the fact that there is always a chance for human error to occur unless the process is entirely automated using advanced tools like PostGrid.

 Also Read: What is Address Deduplication?

Suppose a business uses an address verification tool for getting accurate addresses, and the address text is copied onto the envelope/postcard/package. In this case, there is a chance the address is not copied entirely or accurately. Such mistakes could go easily unnoticed if not subjected to a double-check.

Therefore, you need to look through the addresses written on the envelopes carefully. This process can be included even for a fully automated system as a safeguard against unprecedented errors. After you have checked the delivery and return addresses, you have them taken to the post office to be sent to the country's PO boxes.

Abbreviations & Periods:

We know that you might be wondering about the abbreviations or periods. Can't we use it now?

The answer is that it is better not to use Abbreviations or periods when addressing a P.O. BOX.

According to a standard format suggested by the USPS, you must omit all periods (along with the commas) and use standard abbreviations when writing the address. For Example:

Instead of:
VANYA SCOTT,
P.O. BOX. 2233
Atlanta, GA, 30303

Write:
VANYA SCOTT
PO BOX 2233
ATLANTA GA 30303

Easy, right?

Also Read: Does UPS Deliver to PO Boxes

When sending postal mail to a P.O. box address, certain things must be kept in mind, and we have already discussed the steps on how to address mail to a P.O. box. However, another aspect that you should consider is positioning the PO box number in the address block.

Typically, the address block consists of all the lines that we see in an address, and how you write it can directly affect your mail's handling efficiency. How?

Well, an address written in the correct format is easier to sort and be forwarded, and hence they end up being the first one to go, whereas the one using the wrong format may get chucked to be sorted later.

Always begin a mailing address with the recipient’s name and, as mentioned before, make it roughly centered on the envelope. Next to the name comes the business title, and then comes the post office box number. You can include the rest of the details like city, state, and ZIP code in the final line. It doesn’t matter if the post you are sending is a domestic one or an international one.

Make sure that you write the address in the relevant format. Align each line of the address to the left in accordance with USPS standards. It is also best if you can use capital letters for all words as well as abbreviations to avoid any unnecessary confusion.

Do not forget that you should avoid using commas and periods while writing the address. Use the same format for writing the return address and, as mentioned before, position it in the top-left corner of the envelope.

How to Handle Special Business Cases for P.O. Box Addresses

Formatting the address for a standard business P.O. Box might be straightforward. However, many business situations often need special routing requirements. For example, you might want to direct the mailer to a specific employee or get deliveries from a private shipping company. 

Here’s what you need to do to prepare for such situations: 

The Use of “Care of” (C/O) for Particular Employees or Departments  

Any large organization will have hundreds of employees and multiple departments. It is common to get your mailers lost if you don’t address them properly. So, you should use an “ATTN” (Attention) or “C/O” (Care of) line before the name. It will ensure that your mailer goes to the correct desk once USPS completes the delivery. 

According to USPS, the “C/O” line should be placed above the delivery address line like this: 

Dual Addressing With Street Address and P.O. Box 

Some businesses might have both a physical street address and a P.O. Box. Then, the sender could include both addresses on an envelope. USPS relies on strict rules for dual addressing. The postal carrier would only deliver the mailer to the address line immediately mentioned above the City, State, and ZIP Code line. So, if you want the mail to go to their PO, then place the number right above this line and vice versa. 

Dual Addressing Example: 

Now, if you reverse the order in the above example, then USPS will route the mail to the physical street address instead of the P.O. Box. 

Using Private Carriers to Deliver at a P.O. Box 

There’s a common misconception that private carriers like FedEx, UPS, or Amazon cannot deliver mail or packages to a business P.O. Box. This theory might be true for standard P.O. Box addresses, but USPS provides an exclusive solution for businesses called the Premium P.O. Box Service Street Addressing (PBSA).

These businesses have to sign the PS Form 1093-A at a participating Post Office. After this, the Post Office can legally accept a private carrier on behalf of that particular P.O. Box. For such businesses, use the physical street address of their Post Office, followed by their P.O. Box number formatted as a “#” or “UNIT” designation. So, USPS allows private carriers to recognize this address as a physical location and deliver mail items. 

Addressing Example Using Private Carriers: 

 Please note: The business must sign up for the Street Addressing service at the local Post Office. Otherwise, this format will be invalid and won’t be applied to all P.O. Boxes. 

International vs Domestic Business P.O. Box Addressing 

When mailing to an international address, the formatting rules will be slightly different to follow both the USPS and the destination country’s postal service. The USPS International Mail Manual (IMM) recommends writing the destination country in full, capital letters, on the last line of the address block. So, you should never use the abbreviation of the destination country. 

Each country might have its own terminology for P.O. Boxes. For instance, French-speaking countries often prefer using “BP” Boîte Postale) or “CP” (Case Postale). For this reason, it is necessary to study the destination country’s address specifications. 

Canadian Business P.O. Box Address Example 

Canadian addresses have the postal code on the same line as the city and province, on the consecutive line. 

UK Business P.O. Box Address Example 

For UK addresses, we write the town/city in all caps after the P.O. Box line. Then, mention the postal code before the country line. 

When dealing with postal deliveries made to PO boxes, especially in large numbers that are often seen in businesses and corporate houses, it is always best to understand how a PO box works. This does not mean that the management of PO boxes is complicated or resource-heavy, but there are some rules and regulations that apply to PO box addresses. Below, we discuss the basics of PO boxes, how they work, and the specifications of packages or posts made to them.

How do PO Boxes Work?

As we have already discussed, a PO box is basically a storage place in the post office’s lobby area, which the recipients use for storing their postal mail away from their personal or business addresses. Access to these PO boxes is secured through a key or a combination lock. Furthermore, the PO boxes are accessible to their owners 24/7, making it easier for businesses and individuals to access their postal mail regardless of what time it is.

A person can opt to rent a PO box in any post office of their choice, but businesses and individuals choose a PO box address that is nearest to their location. However, this flexibility of choosing the PO box location can come in handy in some cases where the direct mail is managed by a third party. It allows that person to easily access and manage the postal mail for a company for an individual that he/she is working for.

Businesses or companies should be aware that PO boxes are not the best choice for receiving high volumes of postal mail; neither do they support private shipping carriers like UPS, FedEx, and Amazon. If you were thinking of coming up with a system that would incorporate USPS and private shipping carriers through a PO box address, that is not going to happen, at least for the time being.

Apart from this, you should also note that certain limitations exist when it comes to the size of the package sent to a PO box address. The PO boxes are built in a specific dimension, and it goes without saying that they can not possibly hold anything larger than their size. Suppose the mail does not fit into your PO box. The recipient will then have to collect it directly from a window clerk. This is not desirable for most people as it is significantly less convenient, and therefore, it is always best to follow the apt package sizes for your PO box postal deliveries.

The following table shows the five major PO box sizes that are widely used today.

Also Read: PO Box–Only ZIP Codes