Postcodes for PO Boxes Explained

A PO box, or post office box, is a locked mailbox rented at a post office. Because mail is collected by the customer rather than delivered to a door, the box address uses the postcode of the post office or sorting facility rather than that of a street.

How the address is written

A PO box address usually contains the box number, the name of the post office or town, and the postcode. Some operators publish a dedicated code range for boxes, so all PO boxes at one office share a code. Others simply use the code of the office's area. The exact rule is set by the national operator.

Why PO boxes exist

People and businesses use them when:

• there is no street delivery in their area
• they want a stable mailing address that does not change when they move
• they want mail held in a secure place
• the business handles large volumes and wants to collect them in one go

Limits

A PO box address does not tell you where someone lives. Some deliveries, especially by couriers and for large parcels, cannot use one. Online stores often ask for a street address in addition, for that reason. See why postcodes matter for e-commerce for more on checkout rules.

Postcode versus physical location

The postcode of a PO box tells the operator where the box is, not where the customer is. That is a clear example of the difference between a postal code and a place, which is explored further in postcode vs address vs coordinates.

Related special cases

Large receivers can also have codes to themselves; see postcodes for large organisations. For how codes are given out in general, read how postcodes are assigned.

Adding a precise location

If you need people to visit your premises, rather than send post to a box, a PO box code is no help. Give the street address, and consider an exact-location code. UPCS can generate one for the entrance on the map, and it is meant to accompany the street address.