First-Class Mail & Postage | USPS
https://www.usps.com/ship/first-class-mail.htm
Large First-Class envelopes (flats) that exceed maximum dimensions or are rigid, non-rectangular, or not uniformly thick are charged package prices and shipped with USPS Ground Advantage. TIP: Use the USPS®Price Calculator tool to calculate your domestic postage costs. You’ll need to know your mailpiece’s weight, shape, and size measurements. Calcu...
Large First-Class envelopes (flats) that exceed maximum dimensions or are rigid, non-rectangular, or not uniformly thick are charged package prices and shipped with USPS Ground Advantage. TIP: Use the USPS®Price Calculator tool to calculate your domestic postage costs. You’ll need to know your mailpiece’s weight, shape, and size measurements. Calcu...
DA: 57 PA: 35 MOZ Rank: 37