How Many Stamps Do I Need To Use?

First Class Postage

The amount of stamps you need on a letter depends on the weight and delivery method. Letters are typically 1-3 ounces. A 1-ounce letter requires ONE first-class stamp, which increased in price in January of 2019 to $0.55. From there, each additional ounce is another $0.15. So a 2 oz letter jumps up to 70 cents and a 3 oz letter jumps to $0.85. However, instead of adding three stamps, you can also buy a single stamp for $0.70 for that two-ounce letter or a three-ounce stamp for $0.85. Some people know upfront they’ll need a bigger value stamp to cover the postage and some just add stamp by stamp to estimate. Either way covers your cost! But remember, the post office will not reimburse for any postage overage you may have paid.

Postcards and Forever Stamps

Types of Stamps


Not mailing a letter? Let’s look at stamps in other scenarios. For a typical postcard, a stamp costs $0.35 but for any larger than 6” x 4 ¼ size, you can use the typical $0.55 first-class stamp. For wedding invitations, you typically need $0.55 in stamps. We’ll discuss them in detail below in “Types of Envelopes.” Oddly shaped envelopes or bulky envelopes obviously change the game and are best determined at the post office rather than going with your most educated guess. But it’s key that you know about forever stamps.

Forever stamps stay the same value as whatever the current First-Class stamp is, regardless if you use them a year down the road when the price of postage may have gone up. You can buy both domestic and global forever stamps. Even stamps that are not forever stamps do not necessarily expire. The rule is “as long as they can be validated as legitimate postage.” So even if they go up in price based on time, they don’t get disregarded for simply being old or unused.

Stamps for Large Flat Envelopes and Small Packages

What about small packages and large flat envelopes? From a 12 to 15 inch large flat envelope that weighs up to 13 oz, you’ll pay as low as $1.00 in first-class mail. Any large envelope that weighs above that 13 oz will be qualified under the small package prices. For small packages that weigh up to 5.99 ounces, you’ll pay $2.66 first class. Packages over that must upgrade from first-class to Priority Mail or Priority Express Mail.

What Does Paper Weigh?

It’s worth noting that a single sheet of notebook or printer paper is about 0.16 ounces and 4 pages of notebook paper plus the envelope itself can be mailed with one First-Class stamp. Depending on the weight of the paper, up to 5 sheets can meet that First Class stamp limit. From there, if you’re sending people paperwork beyond that, you can expect additional ounces costing about $0.15.

Postage Necessary for Other Types of Envelopes

Stamps for Mailing Different Envelopes

There are so many types of envelopes, it can get overwhelming. We’ve only talked about standard envelopes and large flat envelopes so far. There are also padded envelopes, which still fit the size and thickness rules of large flat envelopes. Padded envelopes will ship for $1.00 for the first ounce and $0.15 for each additional ounce. But if you’re sending items other than papers, a padded envelope can quickly get too bulky for this rate. Odd shaped envelopes and wedding invitations, as we discussed vaguely have what’s called the “non-machinable surcharge stamp” at $0.70 for the first ounce and then $0.21 for each additional ounce.

Tips to Save Time with Stamps and Postage!

If you’re reading up on stamps to eliminate time in the post office, another helpful resource at your fingertips is the USPS postage calculator online. Once you know your package’s weight and dimensions, you can input those and see what the site estimates and even buy stamps to print online. This helps save time and effort at the post office as well!

When it comes to making an educated guess, you probably know it’s better to overpay and overestimate than to underestimate and then get your envelope sent back to YOU, needing more postage. Also, before planning a trip to your local post office, it’s always a good idea to check your nearest post office’s hours and to make sure it’s not a post office holiday — if it is, the post office will be closed when you arrive.

We hope these tips helped you better estimate how many stamps and what kind of stamps to use in different mailing scenarios! Happy mailing!