Where the PO Box goes in a mailing address

A PO Box replaces the street address line entirely. You do not include both a street address and a PO Box on the same piece of mail — the postal service will be confused about where to deliver it. Instead, put the PO Box number on the line where you would normally write a house or apartment number and street name.

The standard format is: Name on top, PO Box number on the second line, city and state and ZIP code on the third line. That is all you need. No street address, no apartment number, no building name.

Key Takeaways

  • A PO Box address has three lines: recipient name, PO Box number, and city/state/ZIP — never include a street address alongside it.
  • The PO Box line should read "PO Box [number]" or "P.O. Box [number]" — both formats work, and periods are optional.
  • Online forms that require a street address may not accept PO Boxes; some businesses and government agencies will not ship to PO Boxes at all.
  • If a form rejects your PO Box, you may need to provide a physical street address or use a mailbox rental service that offers street-style addresses.
  • The ZIP code for a PO Box is the ZIP code of the post office branch where the box is located, not your home ZIP code.

The correct three-line format

Write it like this:

Jane Smith PO Box 1234 Denver, CO 80202

The first line is the recipient's name. The second line is "PO Box" followed by the box number — you can write it as "PO Box", "P.O. Box", "POB", or "PO #" and the post office will understand any of them. The third line is the city, state abbreviation, and ZIP code, in that order.

Do not add a street address, suite number, or apartment number. Do not write "PO Box 1234 Main Street" or "PO Box 1234, Apt 5" — these confuse mail sorting machines and can cause delivery delays.

When online forms will not accept a PO Box

Many websites and businesses have address fields that are programmed to reject PO Boxes. This happens most often with online retailers, shipping companies, and government agencies. Amazon, for example, will not deliver packages to a PO Box. Banks, insurance companies, and credit card issuers often will not either.

If a form rejects your PO Box, you have a few options. You can provide a physical street address if you have one — a home address, a workplace address, or a friend's address. You can also contact the business directly and ask whether they accept PO Boxes; some do, but their website form just does not have the field set up correctly. A third option is to use a mailbox rental service like UPS Store or Mailboxes Etc., which can give you a street-style address that looks like a real building number but is actually a mailbox.

How to find the correct ZIP code for your PO Box

The ZIP code for a PO Box is not your home ZIP code — it is the ZIP code of the post office branch where your box is located. You can find this on your PO Box rental agreement or receipt. If you do not have that document, call the post office branch directly and give them your box number; they will tell you the ZIP code.

You can also search the USPS website by entering the city and state where your post office is located. The ZIP code will be listed under that branch's information. Using the wrong ZIP code will slow down delivery, so it is worth taking the time to confirm it.

Typing a PO Box in different contexts

On a paper envelope, write the PO Box address by hand or type it and print it. The format is the same either way. If you are filling out a form on paper, write "PO Box [number]" on the line labeled "Street Address" or "Address Line 1" — that is the correct place for it.

In an email signature, you can write it the same way: PO Box number, city, state, ZIP on separate lines or all on one line separated by commas. In a document or business letter, follow the same three-line format. The key is consistency: always put the PO Box number where the street address would go, and always include the city, state, and ZIP code.

Common mistakes to avoid

Do not write "Street Address: PO Box 1234" — the label "Street Address" is just a field name and does not need to be part of what you type. Do not include both a PO Box and a street address on the same label. Do not use your home ZIP code instead of the post office ZIP code.

Do not abbreviate "PO Box" in a way that is unclear — "P.O. Box" and "PO Box" are both fine, but "POB" or "PO #" may not be recognized by older mail sorting systems. Stick with "PO Box" or "P.O. Box" if you want to be safe.

Frequently Asked Questions

Can I use a PO Box as my address for a job application or government form?

Most job applications and government forms will accept a PO Box. However, some government agencies and employers require a physical street address for background checks or official records. If the form specifically says "street address required" or rejects your PO Box, contact the organization and ask whether you can provide a physical address instead.

What if I have both a home address and a PO Box — which one do I give?

Give the address where you want the mail to go. If you want something delivered to your home, use your home address. If you want it sent to your PO Box, use the PO Box address. Never list both on the same form unless the form has separate fields for each.

Do I need to include "United States" or "USA" on a PO Box address?

No, not for mail within the United States. If you are sending mail internationally or the recipient is outside the US, then yes, add "USA" on a separate line after the ZIP code. For domestic mail, the state abbreviation and ZIP code are enough.

Why does my mail keep getting returned when I use my PO Box address?

The most common reason is using the wrong ZIP code. Double-check that you are using the ZIP code of the post office branch where your box is located, not your home ZIP code. The second most common reason is that the sender included a street address along with the PO Box, which confuses the sorting system. Ask the sender to use only the PO Box address.