P.O. Box

P.O. box stands for “post office box,” and that’s essentially what it is—a secure box at a local post office where you can receive mail. Each mailbox has its own P.O. box number and street address at a post office location. For this reason, P.O. boxes offer a convenient way to receive mail without having to reveal your real address. As remote mailboxes, they also allow you to collect mail at a location where you don’t have a street address.

P.O. boxes come in several sizes to fit varying personal or professional needs. Typically, you can choose from five sizes, ranging from 3 inches by 5.5 inches to 12 inches by 22.5 inches. The smallest size is enough for several letters and a few rolled magazines, while the largest size can fit multiple packages. 

While anyone can use a P.O. box, it’s particularly common for small businesses. Sole proprietorships or individuals who run their business from home may choose to use a P.O. box address as their professional address to protect their personal information and separate their business and private lives. That said, many states don’t allow formal entities—such as an LLC or corporation—to use P.O. boxes for business registration.

To learn more, read our in-depth guide to P.O. boxes and how to use them.

How a P.O. Box works

To rent a P.O. box, an applicant must submit USPS Form 1093 along with two forms of valid identification. Boxes come in several sizes and are rented on a six-month or annual basis. Once assigned, the renter receives a key or combination to access the box. The post office holds larger packages that do not fit in the box at the counter for pickup.

Fees vary based on the post office location, box size, and rental term.

Common uses

People and businesses use P.O. boxes when they want a separate, secure, or consistent mailing address:

• Home-based business owners use a P.O. box on invoices, business cards, and websites to avoid publishing a home address.
• Freelancers and sole proprietors use one to receive client payments and correspondence without disclosing where they live.
• Nonprofits and small organizations use P.O. boxes to receive donations and official correspondence at a consistent location.
• Frequent travelers or people who relocate often use a P.O. box to maintain a permanent mailing address for bank statements, government notices, and other important mail.

Key limitations

A P.O. box can be useful, but it does not replace every type of address a person or business may need:

• Private carrier limits. A standard P.O. box address may not work for packages from private carriers such as UPS, FedEx, DHL, or Amazon. Some USPS locations offer Street Addressing, which lets the box holder use the post office’s street address with the box number, subject to availability and restrictions.
• Registered office limits. A P.O. box usually cannot replace a registered agent or registered office address where state law requires a physical street address for service of process. Business owners should check the rules for each state filing, license, bank account, or government form.
• Access limits. Access depends on the post office and box lobby hours. Many locations offer extended or 24/7 box access, but hours vary. A P.O. box also requires in-person pickup unless the renter uses a separate forwarding or related service.

P.O. box vs. registered office address

A P.O. box is mainly a mailing address for receiving mail. A registered office or registered agent address is the official address where a business receives service of process and certain legal or government notices. Many states require the registered agent address to be a physical street address, so business owners should confirm state requirements before using a P.O. box in any official filing.

Related terms

These related terms can help explain how P.O. boxes connect to mailing addresses, legal notices, and business filings:

• Service of process: The formal delivery of legal documents to a party; requires a physical address, not a P.O. box.
• Legal notice: Official communications sent to a business; typically not deliverable to a P.O. Box.
• Mailing address: The address to which a person, business, or organization receives mail.
• Virtual mailbox: A virtual mailbox is a service that receives physical mail and lets the user view, manage, or forward it online.

FAQs about P.O. Box

Can a P.O. box be used as a business address?

Yes, a P.O. box can be used as a business mailing address for general correspondence, invoices, and some marketing materials. However, it may not satisfy requirements for a registered agent address, principal business address, bank account, license application, or tax filing if a physical street address is required.

Can a P.O. Box be obtained for free?

USPS offers no-fee P.O. box service to customers in areas where home mail delivery is unavailable. Eligibility is determined by the local post office.

Is there an alternative to a P.O. box?

Yes, a virtual mailbox is one alternative to a P.O. box. A virtual mailbox offers many of the same benefits as a P.O. box—such as privacy and mail forwarding—but digitizes your mail for easy access from anywhere.