How Many Stamps Do You Need? Exact Stamps For …
If it weighs more than 1 ounce it will cost a further 15¢ per ounce. A large A4 Letter (also known as a Flat) weighing up to 1oz will need one 1 x Standard Forever Stamp, 1 x 10¢ stamp & 1 x Postcard stamp. For each additional ounce of weight it will cost 20¢ more to post. To work out exactly how many stamps you need you will need to know: