For mailing a large envelope (also called a "flat") within the United States, the postage depends on the weight of the envelope:
- The base postage for a large envelope up to 1 ounce is $1.50. This typically requires two Domestic Forever stamps plus some additional cents stamps (e.g., two 2ยข stamps) to make up the exact amount, or you can use three Forever stamps and overpay slightly
- For each additional ounce over 1 ounce, add $0.27 in postage. For example, a 2-ounce large envelope costs $1.78, a 3-ounce one costs $2.06, and so on, up to a maximum weight of 13 ounces
- The number of stamps needed will vary depending on the denominations of stamps you use. For instance, 6 Forever stamps can cover postage for an 11-ounce large envelope
In summary, for a large envelope:
- 1 ounce = about $1.50 postage (approx. 2 Forever stamps + small additional stamps)
- Each extra ounce = add $0.27 postage
- Maximum weight = 13 ounces
You can calculate exact postage by adding Forever stamps (each worth $0.66 as of 2024) plus additional ounce stamps or small denomination stamps to meet the required total. Alternatively, you can purchase postage at the post office or online for precise amounts
. Large envelopes must meet USPS size requirements (between 6 1/8 inches high and 12 inches high, 11 1/2 inches long to 15 inches long, and 1/4 to 3/4 inch thick) to qualify for large envelope rates
. If you want to mail a large envelope weighing around 11 ounces, you would need approximately 6 Forever stamps or equivalent postage totaling around $4.30 to $4.50
