Learn everything you need to know about this affordable and easy way to send envelopes and postcards.
Have your mailpiece’s weight, shape, and size measurements on hand, and you can use the USPS Price Calculator tool to easily calculate your domestic postage costs.
Nonmachinable envelopes might be non-rectangular, rigid, unevenly thick, or have non-paper closures, meaning they cannot be processed efficiently by USPS’s automated sorting equipment, and require special handling, resulting in a surcharge in addition to the standard postage.
Yes, First-Class Mail can handle large envelopes, also known as “flats”, up to 12 inches high, 15 inches long, and 3/4 inch thick, with a maximum weight of 13 ounces. Any envelope exceeding this will be classified and priced as a package, typically sent via USPS Ground Advantage.
Large envelopes are not automatically treated as small packages by USPS. Any envelope up to 12″ high, 15″ long, and 3/4″ thick, with a maximum weight of 13 oz, is considered a First-Class “flat” according to USPS. If a large envelope exceeds these dimensions or is nonmachinable, then it will be treated and priced as a package, typically under USPS Ground Advantage.
First-Class Mail is an affordable USPS service for postcards, letters, and large envelopes, typically delivered in 1-5 business days. Prices vary by item type, shape, and weight, starting at $0.73 for a 1 oz letter. While it doesn’t automatically include tracking, optional services like Certified Mail can provide it.
Get 24/7 access to all of the great services from USPS®, UPS®, and more carriers. Print stamps, shipping labels, Certified Mail® forms, and schedule free pickups in minutes so you can get back to running your business.