What is the maximum thickness for flats sent via USPS?

The maximum thickness for flats sent via USPS is indeed 3/4 inch. This specific measurement is important for ensuring that mailpieces are processed correctly and can be accommodated by the USPS sorting systems. Flats are defined as larger and heavier mail items that are not rigid and can be easily handled like a letter, but must adhere to specific size and thickness regulations to qualify for that classification.

By allowing flats up to 3/4 inch in thickness, USPS aims to facilitate efficient mailing options for items such as brochures, catalogs, and other similar materials without compromising the structural integrity necessary for automated processing. Items exceeding this thickness may have to be classified differently, resulting in higher postage rates or different handling procedures. Understanding this limit helps retailers and individuals prepare their mail appropriately, ensuring it meets USPS standards for pricing and delivery.