Most standard birthday cards, Christmas cards and greeting cards need one ordinary Forever stamp. That answer applies when the sealed envelope is rectangular, flexible, within letter dimensions and weighs no more than one ounce. Use more postage if the card is heavy, square, rigid, unusually thick or contains raised decorations.
Quick greeting-card postage guide
| Finished card and envelope | Typical postage | Ordinary Forever stamps |
|---|---|---|
| Standard rectangular, flexible, up to 1 oz | $0.82 | 1 |
| Standard rectangular, over 1 oz through 2 oz | $1.11 | 1 Forever plus 29¢ Additional Ounce postage; 2 Forever stamps also cover it but overpay |
| Square or otherwise nonmachinable, up to 1 oz | $1.31 | 1 Butterfly Nonmachinable stamp, or 2 ordinary Forever stamps with overpayment |
| Large, very thick or parcel-shaped card | Depends on classification | Do not estimate from the card alone |
Rates shown are effective July 12, 2026. Always evaluate the sealed envelope, including every insert and decoration.
When one Forever stamp is enough
One current ordinary Forever stamp covers an eligible domestic First-Class Mail letter weighing one ounce or less. A typical flat birthday or holiday card in a standard rectangular envelope often fits that category. The theme of the card does not change postage: a Christmas card uses the same dimensional and weight rules as a birthday, thank-you or sympathy card.
Four checks before you mail the card
- Weigh it sealed. Include photos, gift cards, extra sheets and every insert.
- Check the shape. Square envelopes commonly require the nonmachinable surcharge.
- Test flexibility and thickness. Rigid cards, wax seals, buttons, clasps and uneven objects may prevent machine processing or change the mail class.
- Confirm dimensions. An oversized or overly thick piece may be priced as a large envelope or parcel rather than a letter.
Birthday cards and Christmas cards follow the same rule
You can use any genuine, unused ordinary Forever stamp on an eligible birthday or Christmas card; the stamp artwork does not need to match the occasion. One stamp is usually enough for a conventional card under one ounce. Boxed holiday cards can vary, so do not assume every design in a package has the same sealed weight or machinability.
What to do with a square or decorated card
A square, rigid or uneven card can require the nonmachinable-letter price even when it weighs less than one ounce. At current rates, that total is $1.31. A Butterfly Nonmachinable Surcharge stamp is designed for this category. Two ordinary Forever stamps total $1.64 and cover the amount, but overpay by $0.33. See the full rules for using Forever stamps on square envelopes and the exact Butterfly stamp conversion.
Frequently asked questions
How many Forever stamps do I need for a birthday card?
Use one for a standard rectangular, flexible domestic card weighing no more than one ounce. Recalculate if the sealed card is heavy, square, thick or rigid.
Can I use Forever stamps for Christmas cards?
Yes. Genuine unused Forever stamps can pay postage on eligible Christmas cards. The card’s finished weight, size, shape and flexibility determine whether one is enough.
Does a gift card make the envelope need more postage?
It can add weight, thickness or rigidity. Weigh and inspect the finished envelope instead of relying on the greeting card’s printed size.
Should I use two Forever stamps if I am unsure?
Extra postage can prevent a shortfall, but it may waste money and does not correct an ineligible letter shape or parcel classification. Weigh the piece and use the USPS calculator or ask a clerk when uncertain.
Rates and rules checked September 1, 2026: USPS Notice 123; USPS DMM 201. Rates and mailing standards can change.