Question: how many stamps do i need on a birthday card?
Answer: It depends upon the size and weight of the card. If it's less than 11 1/2 inches in length, and less than 6 1/8 inches in height, and under an ounce in weight, it's 50-cents, or one "forever" stamp. If it's up to 2 ounces in weight, it's 71-cents. Add 21-cents for each additional ounce.