How much postage does a letter need?
A letter to USPS is a flexible, rectangular envelope up to 11 1/2 by 6 1/8 inches, 1/4 inch thick and 3.5 ounces. Its postage goes by weight, and USPS kept the extra ounce price at 29 cents in its July 2026 price change.
| Weight | Stamped price | Exact stamps | Forever stamps only | Metered price |
|---|---|---|---|---|
| Up to 1 oz | $0.82 | 1 Forever stamp | 1 Forever stamp | $0.78 |
| Up to 2 oz | $1.11 | 1 Forever stamp and 1 additional ounce stamp | 2 Forever stamps, $1.64 | $1.07 |
| Up to 3 oz | $1.40 | 1 Forever stamp and 2 additional ounce stamps | 2 Forever stamps, $1.64 | $1.36 |
| Up to 3.5 oz | $1.69 | 1 Forever stamp and 3 additional ounce stamps | 3 Forever stamps, $2.46 | $1.65 |
USPS doesn't give change on stamps, so two Forever stamps on a 2 ounce letter pay $1.64 for $1.11 of postage. They are still the simple choice when you have no additional ounce stamps at home, and two of them cover any letter up to 3 ounces. Metered prices, which are 4 cents lower, apply to postage printed by a postage meter or bought through online postage.
How do I know if my letter weighs more than 1 ounce?
Weigh the sealed envelope with everything inside it on a kitchen or postal scale, and round up, because USPS prices by the ounce "not over." A letter that weighs 1.1 ounces pays the 2 ounce price. If you don't have a scale, the self service kiosk or the counter at a post office will weigh it for you. For the same mailer every time, weigh one once and reuse the number.
What makes a letter need extra postage?
USPS adds a $0.49 nonmachinable surcharge to a letter its sorting machines can't handle, which makes a 1 ounce letter $1.31. Under section 101 of USPS's Domestic Mail Manual, a letter is nonmachinable in any of these cases.
- Its length divided by its height comes out under 1.3 or over 2.5, which is why a square card costs more.
- It is too stiff to bend around the turns of a sorting belt.
- It has a clasp, a string or a button, or something lumpy like a coin, a key or a pen inside.
- Its outside is plastic.
- The address runs along the short side instead of the long one.
A nonmachinable letter is sorted by hand, which also means a USPS barcode on it usually gets few scans or none. Our nonmachinable surcharge guide covers each cause, and the letter checker tells you if your envelope passes.
How many stamps does a large envelope need?
An envelope bigger than a letter, or thicker than 1/4 inch, or heavier than 3.5 ounces, goes as a large envelope, which USPS also calls a flat. It can be up to 15 by 12 inches, 3/4 inch thick and 13 ounces, as long as it stays flexible and evenly thick. A 9 by 12 envelope is the usual example, and it starts at $1.69 for 1 ounce, so even a light one needs more than a single Forever stamp.
| Weight | Price | Forever stamps only |
|---|---|---|
| Up to 1 oz | $1.69 | 3 Forever stamps, $2.46 |
| Up to 2 oz | $1.98 | 3 Forever stamps, $2.46 |
| Up to 3 oz | $2.27 | 3 Forever stamps, $2.46 |
| Up to 4 oz | $2.56 | 4 Forever stamps, $3.28 |
| Up to 5 oz | $2.85 | 4 Forever stamps, $3.28 |
| Up to 6 oz | $3.14 | 4 Forever stamps, $3.28 |
| Up to 7 oz | $3.43 | 5 Forever stamps, $4.10 |
| Up to 8 oz | $3.72 | 5 Forever stamps, $4.10 |
| Up to 9 oz | $4.02 | 5 Forever stamps, $4.10 |
| Up to 10 oz | $4.32 | 6 Forever stamps, $4.92 |
| Up to 11 oz | $4.62 | 6 Forever stamps, $4.92 |
| Up to 12 oz | $4.93 | 7 Forever stamps, $5.74 |
| Up to 13 oz | $5.24 | 7 Forever stamps, $5.74 |
A large envelope that is rigid, not rectangular or not evenly thick pays package prices instead, and anything over 13 ounces goes as Priority Mail or USPS Ground Advantage.
How many stamps for a postcard or a letter to another country?
A postcard costs $0.65, which is what a postcard stamp covers, and a Forever stamp also works on one if you don't mind paying the letter price. A 1 ounce letter to another country costs $1.75, the price of one Global Forever stamp, and heavier international letters cost more by weight and country.
What is a Forever stamp worth?
A Forever stamp is always worth whatever a 1 ounce stamped letter costs on the day you use it, no matter what you paid for it. USPS raised that price from 78 cents to 82 cents on July 12, 2026, so a Forever stamp bought before then still mails a 1 ounce letter today.
Does a tracked letter need more stamps?
No. A letter with a USPS Intelligent Mail barcode printed above the address pays the same postage as any other letter. PigeonTrail prints that barcode with the address, so one Forever stamp on a 1 ounce letter still covers it and you can follow every USPS scan on the way. Our page on First Class Mail tracking compares every way to track a letter.
Questions
How many stamps do I need for a letter?
One Forever stamp, $0.82, mails a standard letter that weighs 1 ounce or less. Each extra ounce adds $0.29, up to 3.5 ounces, on USPS's prices since October 4, 2026.
How much postage does a 2 ounce letter need?
A 2 ounce letter costs $1.11, which is one Forever stamp plus one $0.29 additional ounce stamp. Two Forever stamps also cover it.
How many stamps does a 9 by 12 envelope need?
A 9 by 12 large envelope costs $1.69 for 1 ounce and goes up by about 30 cents an ounce, so three Forever stamps cover one that weighs up to 3 ounces.
Does a square envelope need extra postage?
Yes. A square letter is nonmachinable, so it costs $0.82 plus the $0.49 surcharge, $1.31 in all, for 1 ounce.
How much is a Forever stamp now?
A Forever stamp has cost $0.82 since July 12, 2026, and it is always worth the 1 ounce stamped letter price on the day you use it.
Can I put two Forever stamps on a heavy letter?
Yes. Two Forever stamps pay $1.64, which covers any letter up to 3 ounces. USPS doesn't give change for the extra.
Sources
- USPS, Notice 123 price list, effective October 4, 2026: pe.usps.com/text/dmm300/Notice123.htm
- USPS, "U.S. Postal Service Recommends New Prices for July", April 9, 2026, on the July 12, 2026 stamp price: about.usps.com
- USPS, Domestic Mail Manual 101, physical standards for letters and flats, read October 21, 2026: pe.usps.com/text/dmm300/101.htm