Large envelopes (flats) start at $1.63. All postcards and envelopes (or flats) must be rectangular, otherwise an additional charge may apply. Additional size restrictions apply depending on the …

* Large Envelopes exceed one or more of the letter size maximum dimensions. The maximum size for a flat provides plenty of room to put lots of material in the envelope. But keep in mind …

Step 1: Choose Envelope or Postcard Envelopes are for sending flat, flexible things, like letters, cards, checks, forms, and other paper goods. For just 1 $0.78 First-Class Mail ® Forever ® …

Jul 12, 2025 · All First-Class Mail ® items over 13 ounces are sent at the Priority Mail service... dimension or via Flat Rate envelopes or boxes in a fast and affordable way.

Learn USPS envelope dimensions, letter size rules, and large envelope limits. Save time and postage costs when mailing letters and business items.

6 days ago · This document is for mailers who are sending flat-size mail (such as large envelopes) at Automation and Presorted First-Class Mail prices. To use these prices, you …

Apr 7, 2025 · When it comes to mailing large envelopes, knowing how the USPS classifies them is crucial for both accurate postage and delivery. Whether you are sending out invitations, …

When a piece of First-Class Mail exceeds any one of the maximum measurements of a letter, it is classified and priced as a large envelope (flat). The maximum weight for letter-size pieces is …

Large Envelopes & Flats: Can be up to 12" tall x 15" long, 3/4" thick, cannot weigh more than 13 ounces, and must be in uniformly shaped flexible packaging to qualify for the First-Class Mail …

Flats must be: Have four square corners (or finished corners not exceeding a radius of 0.125 (1/8) inch. Uniformly thick. Unwrapped, sleeved, wrapped, or enveloped. Flats not meeting the …