Short answer: The correct PO Box address format has three lines. Line one is the name. Line two is PO BOX and the number.
Line three is the city, state, and ZIP code.
Leave off any street address unless you have signed up for Street Addressing. A mixed address confuses sorting. It can delay or return your mail.
USPS machines sort mail by scanning the address block. An extra line or a wrong word in the wrong spot can send a letter to the wrong slot. The format itself is simple once you see it laid out, and the mistakes people make are just as simple to avoid.
The correct PO Box address format
Write the address in exactly this order.
| Line | What goes here | Example |
|---|---|---|
| Line 1 | Recipient name | Jordan Miller |
| Line 2 | PO BOX plus the number | PO BOX 4521 |
| Line 3 | City, state, ZIP code | Austin, TX 78767 |
Put together, that reads: Jordan Miller, PO BOX 4521, Austin, TX 78767. That is the entire correct PO Box address format, with nothing else added.
How to write a PO Box address, line by line
The name line takes the actual recipient, not a nickname or a shortened version. If the box has more than one authorized user, pick the name the sender actually knows.
The box line is where most confusion starts. Write PO BOX, then the number. Add no apartment number, suite, or street name anywhere on that line.
The city, state, and ZIP must match the Post Office that issued the box, not your home city. Use the ZIP code printed on your box paperwork. A nearby ZIP for a different station can misroute mail.
PO Box, P.O. Box, or Post Office Box: does it matter?
USPS accepts PO BOX, P.O. Box, and Post Office Box as equivalent on an envelope. Its scanning software reads all three the same way.
For consistency, USPS itself uses PO BOX in all capitals on its own materials. That style keeps outgoing mail and business forms uniform, though any of the three will still deliver.
Never mix a street address with a PO Box
Adding your home street address on a separate line is the single most common mistake. It does not matter whether it sits above or below the box number.
Sorting equipment can grab the street line instead of the box line. That misdirects the piece entirely.
The one exception is Street Addressing, a free USPS option some locations offer. It replaces PO BOX with the Post Office street address plus your box number, written as a suite or unit number.
It only works if you have actually enrolled in it first. Without that enrollment, keep the box line as the only location line on the address. For the full explanation of when and how Street Addressing applies, see our guide to how a PO Box works.
Correct vs incorrect examples
| Correct | Incorrect and why |
|---|---|
| Jordan Miller, PO BOX 4521, Austin, TX 78767 | Jordan Miller, 123 Main St Apt 2, PO BOX 4521, Austin, TX 78767 (mixes a street line with the box line) |
| Sunrise Bakery, PO BOX 990, Denver, CO 80202 | Sunrise Bakery, PMB 990, Denver, CO 80202 (PMB is a private mailbox, not a USPS PO Box) |
| Jordan Miller, PO BOX 4521, Austin, TX 78767 | Jordan Miller, PO BOX 4521, Austin, TX 78701 (wrong ZIP code for that box’s actual station) |
Addressing a business PO Box
A business address follows the same three line shape. The company name goes on the first line instead of a person.
Add an attention line only if a specific person should open the mail. Format it as Attn plus the name, placed above the company name.
Keep the box line identical to a personal address: PO BOX and the number, nothing else. Before you rely on a PO Box for business mail at scale, check whether your carrier actually delivers there. Our shipping cost comparison shows how USPS, UPS, and FedEx treat PO Boxes differently.
Sending international mail to a PO Box
USPS accepts a PO Box as the destination for most international mail. The format is the same three lines used for domestic mail.
Add United States of America as a final line if the sender is mailing from outside the country. Customs forms attached to a package still list the recipient information exactly as written on the box.
Keep the box number and ZIP consistent across the envelope and any customs form. A mismatch there can hold up clearance.
Common mistakes that delay or return mail
Beyond mixing in a street address, a few smaller errors cause real delays. Omitting the number after PO BOX is one. An address with no box number cannot be sorted to a specific slot.
Using PMB instead of PO Box is another common mistake. PMB refers to a private mailbox from a retail shipping store, not a USPS box, and the two are not interchangeable on paper.
A stale ZIP code from an old box or a nearby station rounds out the common list. When in doubt, copy the address directly from your PO Box paperwork instead of typing it from memory.
Frequently asked questions
What is the correct PO Box address format?
Name on the first line, PO BOX and the number on the second line, then city, state, and ZIP code on the third line. No street address belongs in that block unless you use Street Addressing.
Do I write PO Box or P.O. Box?
Either style delivers correctly, since USPS scanning software reads both the same way. USPS itself uses PO BOX in capitals on its own materials, so that is the safest default.
Can I include my street address along with my PO Box?
Not unless you have enrolled in Street Addressing at your Post Office. Adding a street address on your own can confuse sorting and delay the piece.
Is PMB the same as a PO Box?
No. PMB stands for private mailbox, a service sold by retail shipping stores, and it is a different system from a USPS PO Box.
What ZIP code do I use for a PO Box address?
Use the exact ZIP code printed on your PO Box paperwork or lease agreement. A nearby ZIP for a different Post Office can send your mail to the wrong station.
Can international mail be sent to a PO Box?
Yes, in most cases. Use the standard three line format and add United States of America as the final line for mail coming from abroad.
The bottom line
The correct PO Box address format is three lines: name, PO BOX and the number, then city, state, and ZIP. Nothing else belongs in that block unless Street Addressing applies.
Copy the exact wording from your box paperwork rather than guessing. Skip PMB entirely, since it means something different.
Once the format is right, your mail sorts correctly every time. For the full picture of what a PO Box does and does not receive, see our guide to how to get a PO Box and our breakdown of what a PO Box costs.