Direct Mail Marketing

How to Mail to a PO Box: Business and Corporate Use Cases

September 15, 2020

A street address is a standard format of contact information used on most mail pieces. Yet many organizations and individuals prefer mailing to a PO box. This may even be the only option they offer. Hence, anyone who regularly uses direct mail should know how PO boxes work and how mailing to a PO box differs from regular mailing.

In today’s article, we’re going to answer all the main questions about mailing to a PO box. Read our blog to find out:

  • What is a PO box address?
  • How to write a PO box address: format and guidelines
  • How do PO boxes work, and what mail sizes are they suitable for?
  • PO box business uses cases: When mailing to a PO box is better than using a street address?

What is a PO Box Address?

A PO box mailing address is the address of a numbered box in a post office where the letters of a specific person or organization are kept. It is usually a 2 to 5 digit number that represents the location of the postal box.

Businesses and individuals rent PO boxes to receive mail directly to the post office and store it there. This speeds up the delivery, makes mailing to a PO box more secure than regular mail, and enables the recipient to get an alternative mail address, which is an excellent option for someone who doesn’t want to get mail to their home or business address.

How to Write a PO Box Address: Format and Guidelines

Mailing to a PO box is easy once you learn where to fill out the address and what contact information to provide. So each time you are reaching out to people who rent a PO box, make sure to follow the next steps:


Step 1. How to Write a PO Box Address: Write the Recipient’s Address in the Middle

Start writing the delivery address in the center. Put the first and the last name of the recipient on the first address line. If you are addressing a company or organization, put its name right below the recipient’s name. Next, you need to indicate the PO box number by writing the “PO box” + 2-5 digit number. The USPS prefers senders to leave out all punctuation since this simplifies the filtering and scanning process. The last line must include the ZIP code, city, and state.

Step 2. How to Write a PO Box Address: Provide the Return Address

Leave the return address in the upper lefthand corner. The return address is necessary to instantly inform the recipient who is the sender and get back the mail piece if undelivered.

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Step 3. How to Write a PO Box Address: Double-check the Address Information and Send the Mail

Carefully look through everything you’ve written on the envelope. Once you check the delivery and return addresses, you can take the mail to the post office and send it to one of the box locations.

Note. If you deal with large volumes of direct mail, consider partially or fully automating it. You will no longer have to write mailing addresses manually, bring mail to the United States Postal Service, and take care of delivery. Inkit’s mail automation services can render, print, deliver, and track tailored mailpieces for you.

How Do PO Boxes Work and What Mail Sizes Are They Suitable For?

Whether you are mailing to a PO box or want to arrange one for yourself, you need to know how PO boxes work. Even though there is nothing complicated in managing a PO box, some rules and limitations still apply. So let’s discuss the basics.

How Do PO Boxes Work?

A PO box is a storage place in the post office’s lobby area where the specific recipient’s incoming mail is stored. The owner can lock the box with a key or a combination lock and access the deliveries 24/7. Even though one can rent a PO box in any post office, in most cases, mail recipients opt for the closest locations.

Pay attention that post office boxes aren’t suitable for high volumes of mail and don’t support private shipping carriers, including UPS, FedEx, and Amazon.

Besides, when deciding whether to use a PO box, you should keep in mind the sizing of packages. If the mailpiece doesn’t fit into your box, you will need to collect it from a window clerk. Below are the main 5 PO box sizes to pick from:

  • X-Small (3″ x 5 1/2″ x 14 3/4″). The PO box can accommodate up to 2 rolled magazines or 10-15 letter-sized envelopes
  • Small (5″ x 5 1/2″ x 14 3/4″). The small box fits up to 5 rolled magazines or 10-15 letter-sized envelopes
  • Medium (11″ x 5 1/2” x 14 3/4″). This PO box would be wide enough for large envelopes and magazines if they are stacked flat.
  • Large (11″ x 11″ x 14 3/4″). You can put two shoeboxes here and 10-15 letters.
  • X-Large (22 1/2″ x 12″ x 14 3/4″). The largest box is suitable for parcels and Flat Rate Boxes.

For more information on mailing size, read our complete guide on postcard dimensions to help you understand what mail sizes can satisfy your personal or business needs.

PO Box Business Use Cases: Benefits of Mailing to a PO Box over Using a Street Address


If you are a startup and don’t want to share your home address, mailing to a PO box can help you look more professional. We’ve all heard about Apple, Amazon, Google, and other world-renowned companies that started in a garage. So in case you are a beginner without a business address, use box rental for official messages. You will be able to communicate with partners and potential customers through direct mail while maintaining your business reputation.

Financial organizations

When banks, insurers, debt collectors, and other institutions need to send critical communications, they often opt for mailing to a PO box over regular street addresses. Since PO boxes are located in post offices, they are more secure than street mailboxes. Therefore, if you need to mail a confidential document or notice, always prefer mailing to a PO box.

confidential letter mail

Online businesses

Similarly to startups, e-commerce, and other digital enterprises don’t always have business addresses. Nevertheless, they still regularly receive print communications and need to share trustworthy contact details. That’s when mailing to a PO box can help. Apply for your personal box in the nearest post office to get well-protected storage for your business communications.

Business owners that frequently travel

Mailing to a PO box gives you the freedom to grab your mail and packages whenever you need it. If you want to protect your letters’ security and privacy while you’re far away, rent a PO box to store your mailings there.

Regardless of multiple mailing uses to a PO, the standard mailing process is still more common, especially once you upgrade it with direct mail automation software for highly-targeted and personalized mail.
Have any questions about automating different kinds of mailing? Let’s talk

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By submitting this form, I confirm that I have read and understood Inkit's Privacy Policy.
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