PO box size selection for package receiving

Chose the wrong PO box size on my first rental and ended up with packages being held at the window rather than fitting in my box. Here is what I learned about selecting the right size.

USPS PO box sizes

USPS offers boxes in five sizes labeled 1 through 5. Size 1 is the smallest — fits standard letter mail and small envelopes. Size 2 is more common and holds small packages up to about the size of a shoebox. Sizes 3 through 5 accommodate progressively larger packages.

For receiving flat envelopes and small padded mailers — the typical format for card deliveries — Size 1 works fine. The padded mailer can be folded slightly to fit, or if it does not fit, it gets a "package waiting" notice and is held at the window, which means a trip to the post office to collect it.

What actually matters

The biggest factor is not the box size but whether the items you receive will fit in the box when you are not checking it daily. If you check the box every day, a small box is fine because you clear it before it fills. If you check it weekly, you need a larger box to avoid notification-requiring overflow.

Most packages from international vendors arrive in flat envelopes with cardboard backing. These fit in a Size 1 or Size 2 box without issues. The packaging format matters as much as the package dimensions.

Mail forwarding services vs PO boxes

If package frequency is high, a mail forwarding service with a physical suite address often makes more sense than a PO box. Forwarding services hold packages regardless of size, provide digital notifications and photo evidence, and forward to any domestic address. The cost is higher but the logistics are simpler for regular receipt of varied package sizes.