How Much Weight Does A Stamp Cover
A standard stamp covers letters up to 1 oz (about 28 grams), but heavier mail, unusual shapes, and international letters all change what you owe. Stamps dont care about the number of sheets. They care about weight.
A single Forever stamp covers: Most regular printer paper weighs around 4 to 5 grams per sheet. Thats why 3 to 5 sheets usually stay under the 1 ounce limit. Once you go past that, youll need extra postage.
How many stamps do you need? Use our free calculator 1 oz = 1 Forever Stamp ($0.78), 1.5 oz = 1 stamp + $0.29, 2 oz = $1.07. Chart covers every weight including 9x12 envelopes. As of January 2026, a Forever Stamp costs $0.78 that covers one ounce of domestic First-Class mail.
But depending on what you are sending, you might need more than one stamp, a different type of stamp entirely, or a completely different mail class. A single Forever stamp covers the first ounce of a qualifying letterbut additional ounces need additional postage. That is why one stamp answers are only reliable when you are sure the piece is 1 oz and does not trigger shape or handling surcharges.
Calculate the postage price for your mail piece based on weight and shape/size. Choose from standard or metric units of measurement and select letter, large envelope, or package options. A First-Class Forever Stamp now costs $0.73, and weight plays a key role in how many stamps youll need.
In this guide, well break down USPS weight classes, postage rates, and how to calculate the right number of stamps for any type of mail. Discover how heavy a letter can be for one stamp and avoid costly mistakes. Learn exact weight limits and mail smarter with expert tips today!
For most everyday letters, one Forever Stamp is enough. That single stamp covers the first ounce of a First-Class Mail letter as long as your envelope is the right size and weight. As of , the USPS rate for a First-Class Mail letter (1 oz) is $0.78.
As of 2022, the postage for a standard 1 ounce letter is $0.60. This means any single envelope weighing 1 ounce or less can be mailed with just one forever first-class stamp. These special stamps allow you to lock in the current 1 ounce rate regardless of future price increases.
