

Priority Mail Flat Rate was really designed as a consumer product, and is not ideal for most business shippers.

View comparisons of Medium and Large Flat Rate Boxes vs.

You can’t use your own packaging, which can impact your customer's experience.This simplifies shipping a lot, but that simplicity comes with downsides: The idea behind Priority Mail Flat Rate is that if you can fit something into a Flat Rate-branded box, there’s just one price to pay, no matter how much it weighs or where it’s going. Flat Rate pricing makes shipping costs easier to understand, but it's usually more expensive
