A PO Box identifies a rented mailbox at a Post Office; a street address identifies a location on a street. A form asking for your physical residence needs information about where you live. Neither an ordinary PO Box nor its USPS Street Addressing version turns the Post Office into your residence.
If checkout says “No PO Boxes,” check the shipping service and the seller’s policy before changing the entry. Replacing PO BOX with APT does not fix an unsupported delivery destination.
Identify the address before choosing a field
| What you have | What it means | What to confirm |
|---|---|---|
| Ordinary street address | A location, with a real apartment or suite where applicable | The recipient uses that location and the address is complete |
| USPS PO Box | An assigned box at a Post Office | The full box address and a service that accepts it |
| PO Box with Street Addressing | A participating Post Office’s supplied street-format mailing address | Enrollment, the exact supplied format and applicable restrictions |
| Private mailbox, or PMB | A mailbox with a commercial mail receiving agency | The operator’s full address and mailbox identifier |
The USPS PO Box service page describes boxes as places where mail waits for collection. A commercial private mailbox is a separate arrangement. Publication 28, section 285 specifies PMB addressing, including PMB or #; a hash sign alone does not tell you which kind of address you have.
Entering a conventional PO Box in an address form
For a mailing form that accepts PO Boxes, this is a practical mapping. Follow dedicated PO Box fields or the site’s instructions when provided.
| Form field | Entry |
|---|---|
| Recipient | The recipient name supplied or confirmed by the box holder |
| Address Line 1 | PO BOX followed by the assigned box number |
| Address Line 2 | Leave empty unless further information is specifically needed |
| City, State and ZIP Code | The matching details supplied for that PO Box |
USPS section 281 specifies the PO BOX format. PO BOX 123 is a format example here, not a mailbox offered for receiving mail. Do not substitute your home ZIP Code or add your home street merely to fill a second line.
If both a street address and a PO Box must appear on a USPS mailpiece, section 215 says the intended delivery address belongs immediately above the city/state/ZIP line, with a matching ZIP Code. Prefer one clear destination. That postal rule does not establish how a particular checkout system interprets two address fields.
Street Addressing is a service you enroll in
USPS offers Street Addressing at participating locations. Use the complete address supplied after confirming the service for your box. Looking up a Post Office on a map and appending a number does not activate it. PostalPro explains the service.
The pattern is shown below; these are labels for the components, not a usable mailing address:
[POST OFFICE STREET ADDRESS] # [ASSIGNED BOX NUMBER]
[SUPPLIED CITY] [STATE] [PO BOX ZIP CODE]
The current USPS customer agreement specifies # plus the box number and rules out replacing it with Suite or Apt. Keep the format your Post Office supplies. If a form rewrites the number as an apartment, ask the sender or Post Office how to proceed.
Publication 28, section 284 describes # or UNIT in its overview. For your box, follow the current customer agreement and the exact format supplied by the Post Office.
The agreement also prohibits using this street-style address as a physical residence or place of business in legal documents. A mailing address does not answer every request for a physical address.
Check the shipping product, not just the carrier logo
| Destination and service | Practical check |
|---|---|
| Conventional PO Box on a UPS shipment | UPS WorldShip guidance calls for a street address and warns about delays, loss of service guarantees and address-correction charges for PO Box entries. Adding a phone number is not a delivery guarantee. |
| Direct domestic US delivery to a PO Box through FedEx | The FedEx US FAQ identifies FedEx Ground Economy as the domestic PO Box option and says it is contract-only. Do not assume an ordinary FedEx label qualifies. |
| An enrolled USPS Street Addressing destination | USPS describes receipt of private-carrier packages that meet its mailing standards. Confirm the location, item restrictions and the seller’s acceptance. |
Ordinary PO Box restrictions and an enrolled Street Addressing arrangement are different cases. Neither the carrier name nor a successful form submission settles every delivery condition.
A short checklist for a rejected address
Check the field’s purpose first: mailing, billing and residential addresses are not interchangeable. Then verify the assigned box number and its city, state and ZIP Code. Confirm Street Addressing enrollment if you intend to use it. Finally, ask the seller which shipping product it will use and whether it accepts that destination; obtain another authorized delivery address when necessary.
For form QA, keep ordinary streets, conventional PO Boxes, enrolled street-style boxes and PMBs as separate cases. The US address generator is a format and test-data tool, not a way to rent a mailbox, activate postal services or establish deliverability. For the basic components, see US address structure.
Official sources were checked on October 16, 2026. No physical shipment was tested for this guide.