As of September 2014, First-Class postage for a single piece of mail weighing 1 ounce or less is 49 cents for a stamped letter-size envelope, 98 cents for a large flat envelope and $2.32 for a parcel. The price increases according to the weight of the envelope or parcel.
The price of postage for First-Class Mail is calculated based on the weight and size of the package being shipped, not on the shipping destination.
First-Class Mail includes letters, cards, flats and parcels weighing 13 ounces or less. Some types of mail commonly sent First-Class are personal correspondence, handwritten or typewritten material and bills. The maximum weight for First-Class letters is 3.5 ounces, and the maximum weight for First-Class parcels is 13 ounces. At over 13 ounces, First-Class Mail becomes Priority Mail, which is subject to different pricing.