How Many Stamps Do I Need To Send A Letter?
Last updated on July 3rd, 2022 at 05:26 pm
Sending a letter seems very simple, but if your letter is overweight or has unusual dimensions, it can be difficult to figure out how many stamps it will need. Fortunately, the post office provides very clear rules about how much postage a letter or package needs.

How many stamps do I need to send a letter?
How many stamps you need to mail a standard-sized letter depends on what the current rate is for sending mail. Both the cost to mail a letter and the cost of postage such as Forever stamps fluctuate from time to time, so it’s a good idea to double-check before you send anything.
However, as of 2021, a standard-sized envelope costs $0.58 to mail. To mail a standard letter, you can either use 58 cents worth of stamps, or you can use a forever stamp, which is always enough to mail a standard letter.
A standard-sized letter is any letter that’s rectangular in shape and weighs an ounce or less. For a piece of mail to qualify as a letter, the envelope must be rectangular in shape.
The height must be at least 3.5 inches and can’t exceed 6.125 inches, and the width must be at least 5 inches and can’t exceed 11.5 inches.

However, square letters or cards and smaller letters can be sent with the same forever postage.
There are a few things that can make a letter qualify as non-machinable. This includes any decorations on the front, such as a wax seal or puffy stickers, a letter that’s too thick, a letter that’s too rigid, or an address written sideways.
If your letter is non-machinable, you’ll need to pay about $0.15 in additional postage.

What is a Forever stamp?
Forever stamps are stamps that are good forever, no matter when they were purchased, how much they were originally purchased for, or how old they are.
Forever stamps can also be used no matter how other stamp prices or mail costs change. For example, even if the cost of mailing a standard letter goes up, a single Forever stamp can still be used to mail the letter, and it will be sufficient postage.
One Forever stamp is also generally enough postage to mail a postcard, a greeting card, or a square letter.
If you have a heavy, oversized, or non-machinable letter, you can add an extra Forever stamp to cover the postage.
However, adding a stamp of a smaller monetary denomination is often a better choice, as Forever stamps generally cost about $0.50 each.
If you’re mailing a standard-sized letter internationally, you can use a Global Forever stamp. As of 2021, Global Forever stamps cost $1.15.
What happens if enough postage isn’t used?
If enough postage isn’t used, the post office will deliver the mail anyway, but it will come with a “Postage Due” notification. If the recipient of the mail wants to receive the mail, they’ll need to pay the missing postage.
However, if the recipient doesn’t want to pay the postage, the letter will be returned to the sender. Sometimes, the post office decides not to mail the letter at all but simply returns it to the sender with a “Postage Due” stamp on it.
If your letter comes back to you because there is postage due, you can add the necessary postage to bring it up to the correct amount and cross out the postage due mark. Then, you can simply mail the letter again.
If there is no return address on a letter with insufficient postage and the recipient refuses to pay the postage due, the post office may open the mail to try to find the sender. Otherwise, the mail becomes what’s known as dead mail, and it’s disposed of.
If you’re shipping a letter or package as Priority or Express mail, even if you need it to get somewhere by a certain date, the post office can hold your package without shipping it until the additional postage is paid.
If you’ve sent a letter or package as Priority or Global Express mail and the postage is insufficient, the post office will still deliver the package within the designated mailing deadline, but you’ll be charged for the missing postage.

What stamp denominations are available?
Using a Forever stamp or Global Forever stamp is often the easiest way to ensure you’re using enough postage, but if you want to add postage to create the exact amount, the post office sells stamps in several different denominations.
You can buy stamps ranging from 1 to 5 cents, as well as 10 cent stamps, 32 cent stamps, and other stamp denominations going all the way up to $25.00. You can also purchase specific stamps for postcards, nonprofit mail, non-machinable fees, and first-class mail.
The post office also offers stamps for packages weighing a specific amount. Two and three-ounce stamps can be purchased, and there’s a special stamp to use, called the additional ounce stamp, for anything weighing over three ounces.

How much does it cost to mail a package?
How much it costs to mail a package depends almost entirely on the weight of the package, although some oddly shaped packages might cost more or may not be able to be shipped by the post office at all.
Packages that weigh less than 1 pound cost about $2.74 to mail, although this price does fluctuate from time to time.
Packages weighing over 1 pound usually cost about $7 and up, and there is usually a 10 to 25 cent additional charge for each extra pound.
