Postage Rates 2024 Large Envelopes Mail. Prices will rise by an average of 4%, with some individual rates. Postal rates are also calculated by reference to the weight, shape, size and destination.
The baseline postage rate to mail a flat/large envelope has increased from $1.35 to $1.39 in postage, but the price for each additional ounce also stayed the same. The price for the retail flat rate envelope, a significant portion of all priority mail express volume , will increase to $30.45, with the legal size and padded flat rate.