What are the standard box sizes for usp?

The standard box sizes for the United States Postal Service (USPS) include several flat rate options: Small Flat Rate Box (8.69" x 5.44" x 1.44"), Medium Flat Rate Box (11" x 8.5" x 5.5"), and Large Flat Rate Box (12" x 12" x 5.5"). Additionally, there are Regional Rate Boxes A and B with specific dimensions for heavier items. For parcel shipping, USPS also offers various size options based on weight and destination. It's important to check the USPS website for any updates or changes to these sizes.