The Difference Between Apartment Numbers and PO Boxes in USPS Mail Service

When using the United States Postal Service (USPS) to send and receive mail, it is essential to understand the differences between an apartment number and a PO box. Each has its own unique purpose and usage, and knowing the appropriate format for your address can ensure your mail is delivered correctly.

What is an Apartment Number?

Definition: An apartment number identifies a specific unit within a multi-unit residential building, such as an apartment complex or condominium.

Usage: It is used when addressing mail to someone living in a building with multiple residences. For example, if John Smith lives in apartment 5B of a building, the address would be formatted as:

123 Main St Apt 5B 
City State ZIP Code

What is a PO Box?

Definition: A PO Box, or Post Office Box, is a secured mailbox located at a post office that individuals or businesses can rent to receive mail.

Usage: It is used when someone prefers to receive mail at a post office rather than at their physical address. For example, if John Smith has a PO Box, the address would look like this:

PO Box 1234 
City State ZIP Code

Key Differences

Location

An apartment number: refers to a specific unit in a residential building.

PO Box: is a mailbox located at a post office.

Purpose

An apartment number: is used for residential addresses.

PO Box: is used as an alternative to a home address for receiving mail securely.

Access

Apartment: residents can access their apartments directly.

PO Box: holders must go to the post office to retrieve their mail.

Addressing Mail Properly

When addressing mail, using the correct format for either an apartment number or a PO Box is essential for ensuring that the mail is delivered properly. Here are a few unique situations to be aware of:

Region-Specific Formats: In some areas, the USPS may recommend a specific format. For instance, if you live in an area with no mail delivery and the post office advises you to use:

1234 Street Dr 123 this number being PO Box City State ZIP

Reasons for This Format: The post office may use this format to ensure that:

If UPS gets the address, they will know to deliver to a real place. If USPS gets the address, they will know to put it in a PO Box.

This method also allows the USPS to circumvent companies that do not ship to PO Boxes.

Different Roles of Apartment Numbers and PO Boxes in Mail Delivery

Apartment Number: Your apartment number serves as a guide for the mail carrier, indicating where your specific unit is located within the building. Carriers bring mail to your apartment and distribute it directly to each resident, using the apartment number to ensure that the mail is delivered to the correct unit.

PO Box: A PO Box is a separate location where mail is directed. Once the mail is sorted, it is delivered to the post office box clerk, who then distributes the mail to the appropriate PO Boxes. Since these boxes are at the post office, there is no need for a mail carrier to distribute the mail directly to the address, making it more convenient and secure for recipients to collect their mail at a single location.

Knowing these differences can help you choose the best form of mail address depending on your needs and convenience. Whether you prefer the direct delivery of your apartment number or the security of a PO Box, both options offer unique advantages in managing your mail.