Stamps needed for your letter or envelope
How many stamps are needed depends on the weight and on whether it is a letter or a large envelope. Enter both to count your Forever stamps.
Independent site, not the Postal Service: prices read in its own price files.
Example: a 2 oz letter· change a figure to see yours
Letter postage
$1.11
2 Forever stamps ($0.82 each), $0.53 overpaid
| One Forever stamp (1 oz letter) | $0.82 |
| Each extra ounce of a letter | $0.29 |
| Price on January 17, 2027 | $1.11 (stamps do not change) |
Compiled by Radif Partners · How the prices are built
The number of Forever stamps needed is the postage divided by the stamp price, $0.82, rounded up. A letter up to 1 ounce takes one stamp. A 2-ounce letter costs $1.11 and a 3-ounce letter $1.40: two stamps each, since each Forever stamp is worth a full 1-ounce letter and you overpay a few cents. Letters stop at 3.5 ounces; above, or if the envelope is larger than letter size, it is a large envelope, often called a flat, with its own scale from $1.69 for 1 ounce to $5.24 for 13 ounces. A 4-ounce large envelope costs $2.56, or 4 Forever stamps. Over 13 ounces, the piece is a package and goes by Ground Advantage. Stamps cannot give change, so buying the exact postage at a counter saves the difference on heavy envelopes.
Stamps needed for a letter
| Letter | Postage | Forever stamps | Overpaid |
|---|---|---|---|
| Letter up to 1 oz | $0.82 | 1 | $0.00 |
| Letter up to 2 oz | $1.11 | 2 | $0.53 |
| Letter up to 3 oz | $1.40 | 2 | $0.24 |
| Letter up to 3.5 oz | $1.69 | 3 | $0.77 |
Stamps needed for a large envelope
A large envelope is a flat piece bigger than a letter, up to 13 ounces. With Forever stamps alone the overpayment grows with the weight; at the counter you pay the exact postage.
| Large envelope | Postage | Forever stamps | Overpaid |
|---|---|---|---|
| Large envelope up to 1 oz | $1.69 | 3 | $0.77 |
| Large envelope up to 2 oz | $1.98 | 3 | $0.48 |
| Large envelope up to 3 oz | $2.27 | 3 | $0.19 |
| Large envelope up to 4 oz | $2.56 | 4 | $0.72 |
| Large envelope up to 6 oz | $3.14 | 4 | $0.14 |
| Large envelope up to 8 oz | $3.72 | 5 | $0.38 |
| Large envelope up to 10 oz | $4.32 | 6 | $0.60 |
| Large envelope up to 13 oz | $5.24 | 7 | $0.50 |
Stamps for another envelope
Example: a 3 oz large envelope· change a figure to see yours
Large envelope postage
$2.27
3 Forever stamps ($0.82 each), $0.19 overpaid
| One Forever stamp (1 oz letter) | $0.82 |
| Each extra ounce of a letter | $0.29 |
| Price on January 17, 2027 | $2.27 (stamps do not change) |
When it is no longer a letter
Weigh before you stamp. A kitchen scale that reads in ounces is enough; round up, since 1.1 ounces pays the 2-ounce price. If you send the same envelope often, weigh one and keep the count of stamps on a note. The counter at a Post Office weighs and prices the piece for you and sells the exact postage, which avoids overpaying on large envelopes, where the gap between the price and a whole number of Forever stamps can reach several dimes.
A letter over 3.5 ounces pays the large envelope scale. A square, rigid or lumpy letter pays the nonmachinable surcharge, see the stamp page. Anything over 13 ounces is a package, see Ground Advantage rates.