How to Know How Many Stamps to Place

Whether you're sending a letter, postcard, large envelope or package, USPS offers a variety of First-Class Mail stamps in different denominations. For mailing typical business letters, you'll often use the standard USPS Forever Stamps. However, you also have cheaper and more expensive stamps that can help account for additional postage costs or help you avoid overpaying postage by using too many Forever Stamps. You can use the current USPS price list and the USPS shipping calculator tool to find your postage cost and determine exactly how many stamps to place.

Understanding USPS Stamp Options

Currently, the USPS stamp options include:

  • Forever Stamps: These are the primary stamps used and cost 55 cents for mailing a 1-ounce letter. These stamps are called "Forever" because if you don't use them this year, their value will remain the same as a regular postage stamp in the future.

  • Postcard Stamps: Costing 35 cents, a postcard stamp works for sending a typical postcard within the United States.

  • Global Forever Stamps: This $1.20 stamp works for mailing a 1-ounce letter internationally.

  • Additional Postage Stamps: When you need to add an extra ounce or some more postage without including another Forever Stamp, you can use incremented stamps in amounts such as 1 cent, 5 cents, 10 cents and 15 cents. You can also buy larger stamps that count for multiple ounces or allow for higher postage prices for packages.

Mailing a Letter

Currently, it costs 55 cents to mail a 1-ounce domestic standard letter with 15-cent increments applying for 2, 3 and 3 1/2 ounces.

So, you can use a single Forever Stamp for mailing a letter weighing an ounce. If you have a letter weighing 3 ounces at a price of 85 cents, you could use a Forever Stamp for the first 55 cents and then two 15-cent stamps to add up to the price. You could also simply attach two Forever Stamps, but this would cause you to overpay the postage.

When sending a 1-ounce international letter, you can use a single Global Forever Stamp costing $1.20 and include another if the letter weighs an additional ounce.

Mailing a Postcard

When you're sending a rectangular postcard domestically, you can simply attach a 35-cent postcard stamp. However, USPS will charge the regular letter rate and require a typical Forever Stamp if your postcard fails any of these tests:

  • Less than 3.5-inches high or more than 4.25-inches high

  • Less than 5-inches long or more than 6-inches long

  • Less than 0.007 of an inch thick or more than 0.016-inches thick

An international postcard will take one $1.20 Global Forever Stamp like a standard letter.

Mailing a Large Envelope

When sending a large envelope up to 12-inches high, 15-inches long and 0.75-inches thick, USPS charges $1.00 for the first ounce with increments of 20 cents for each additional ounce up to a maximum of $3.40 for 13 ounces.

So, if you're sending a large envelope that weighs 6 ounces and costs $2.00 to send, you could purchase the special $2.00 stamp available from USPS. Along with rounding up to use four Forever Stamps, you could use three Forever Stamps with three 15-cent stamps to make up for the extra 35 cents owed.

Mailing a Package

If you need to mail a package using stamps, know that USPS will charge you based on the package's postal zone and its weight. You're limited to First-Class packages of up to 13 ounces with prices ranging from $3.80 to $4.20 for 1 ounce to a maximum of $5.90 to $6.50 for 13 ounces.

For the most accuracy with pricing, you'll want to use the USPS shipping calculator available on the website. You'll need the package's weight, dimensions and the Zip Codes for the shipping and destination locations to plug into the tool. USPS will show a list of different service options, and you'll get the USPS First-Class price needed from that list.

Use your package's price to calculate the mix of stamps that satisfy the requirement. So, if you're paying $3.80 to send a package, you could divide that by 55 cents to get the number of Forever Stamps you can use, which would work out to seven when you round up. Like with the other types of shipments, you can use the smaller and larger stamps to come up with the exact postage and avoid overpaying.