You can mail a package with ordinary stamps. The question is how many, and the intuitive answer overpays.
The worked example
Say the calculator gives you $5.04 and you have Forever stamps at 60 cents each.
Divide: $5.04 ÷ $0.60 = 8.4 stamps. You cannot use four-tenths of a stamp, so the obvious move is nine stamps — $5.40. That works, and you have overpaid for no reason.
The better answer: eight Forever stamps ($4.80) plus a 24-cent additional-ounce stamp. That comes to exactly $5.04.
Make-up denominations exist for precisely this. Keeping a few low-value stamps beside your Forever stamps turns every awkward total into an exact one.
The rates behind it
A one-ounce package goes anywhere in the US for $0.60, typically delivered in 1–3 days. Above that, add $0.24 per ounce, up to 3.5 ounces.
Two single-stamp shortcuts worth knowing: the 84-cent two-ounce stamp and the $1.08 three-ounce stamp. Both are cheaper than assembling the same value from Forever stamps, and quicker to apply.
Choosing the class first
Postage follows from the class, so pick that before counting stamps.
Ground — 2–8 business days, the cheapest option, right when speed does not matter.
Priority Mail — 1–3 days, and flat-rate packaging carries up to 70 lbs (32 kg) for one price regardless of weight. For anything dense this is usually the cheapest route by a wide margin. There are dedicated Priority stamps, so it can be paid with stamps rather than a printed label.
First-Class — 1–3 days, capped at 13 ounces (370 g). This is the band where stamps make the most sense.
Getting the number right
Use the USPS price calculator rather than the rate table: enter both ZIP codes, choose the shape, enter the weight, and it returns the figure. Guessing at a rate table is where the errors come from.
Then check your stamps against that figure before sealing. Underpaid packages may be returned, which costs you the delay as well as the postage.
First-Class packages can be handed to a carrier or dropped in a collection box without a counter visit — provided the postage is right.
Best deals on Forever stamps
Keep three things in the drawer: Forever stamps, additional-ounce stamps, and a scale. Between them you can pay any letter or small-package rate exactly.
Where to buy
The USPS official store for denominated and make-up stamps, or a verified surplus channel such as Forever Stamp Center for Forever stamps in volume.
The short version
Divide the postage by 60 cents and you will get a fraction. Round up and you overpay; add a 24-cent make-up stamp instead and you pay exactly. And for two or three ounces, one dedicated stamp beats a stack of Forever stamps.
More on buying Forever stamps
- 👉 Two-Ounce Stamps for Heavy Letters and Invitations
- 👉 How Do We Figure Out How Many Stamps We Need?
- 👉 The Aspect Ratio Window Is 1.3 to 2.5
USPS professional based in New York with over 12 years of experience in postal operations. She writes about Forever Stamps, offering practical guidance on safe purchasing and mailing practices while closely following USPS policy updates.
