Most standard wedding invitations need one Forever stamp — currently $0.82 — per outer envelope. If you include a pre-addressed RSVP envelope, that reply card needs its own stamp too. So for every guest household, you will typically need two stamps: one for the main invitation and one for the RSVP return envelope.
Current USPS letter rates
As of September 13, 2026, USPS Notice 123 lists $0.82 for an eligible stamped domestic letter up to 1 ounce, $1.11 for 2 ounces, $1.40 for 3 ounces and $1.69 for 3.5 ounces. The additional-ounce increment is $0.29, and a qualifying nonmachinable letter adds $0.49. The schedule took effect July 12, 2026.
These prices apply only after the finished piece is classified correctly. Postcards, flats, packages, international mail and added services use different rules.
Get the right stamps for your wedding →
Wedding Invitation Postage Rules: Weight, Size & Shape
USPS determines postage based on the weight, shape, and thickness of a finished mailpiece — not just the paper inside. Here are the rules that affect most wedding invitations.
If your invitation meets all of those criteria — a flat card or folded card with standard paper inserts in a rectangular envelope — one Forever stamp covers it.
When One Stamp Is Not Enough
Certain invitation styles exceed standard letter requirements and need extra postage:
| Situation | Postage Needed | Common Cause |
|---|---|---|
| Square envelope (e.g., 5×5, 6×6) | $1.31 (non-machinable surcharge) | Square shapes cannot run through sorting machines |
| Envelope over 1 oz but under 2 oz | $0.82 + $0.29 = $1.11 | Heavy card stock, multiple inserts, ribbon, wax seal |
| Envelope over 2 oz but under 3 oz | $0.82 + $0.58 = $1.40 | Thick booklet-style invitations with many pages |
| Rigid insert or non-uniform thickness | $1.31 non-machinable surcharge | Wax seals, charms, layered pockets, magnets |
| International invitation | Starts at $1.75 (varies by destination) | First-Class Mail International letter rate |
See the full 2026 Forever stamp price breakdown →
How Many Stamps for Your Full Wedding? (Planning Calculator)
A complete wedding mailing involves more than just the invitation envelope. Use the table below to estimate your total stamp needs.
Three Types of Wedding Mail Per Household
- Outer invitation envelope — mailed to each guest household (1 Forever stamp if standard)
- RSVP return envelope — pre-stamped and tucked inside the invitation (1 Forever stamp)
- Thank-you card — mailed after the wedding (1 Forever stamp each)
That means for every guest household you are typically looking at 3 Forever stamps total across the entire wedding cycle.
| Guest Households | Invitation Stamps | RSVP Stamps | Thank-You Stamps | Total Stamps | Cost at $0.82 |
|---|---|---|---|---|---|
| 30 | 30 | 30 | 30 | 90 | $70.20 |
| 50 | 50 | 50 | 50 | 150 | $117.00 |
| 75 | 75 | 75 | 75 | 225 | $175.50 |
| 100 | 100 | 100 | 100 | 300 | $234.00 |
| 150 | 150 | 150 | 150 | 450 | $351.00 |
Common Wedding Postage Mistakes
Avoid these frequent errors that send invitations back to sender or cost more than expected:
- Not weighing the full assembly. The paper invitation alone may weigh under 1 oz, but once you add inserts, tissue paper, ribbon, and a wax seal, you may cross the 1 oz threshold. Bring a complete, sealed sample to the post office.
- Forgetting the RSVP stamp. Guests will not mail back your reply card unless you include a pre-stamped return envelope. Budget for this from the start.
- Using a Forever stamp on a square envelope. A 6×6-inch square envelope requires a non-machinable surcharge of $1.31, not $0.82. A single Forever stamp will not cover it — your invitations will arrive with “postage due.”
- USPS rates effective July 12, 2026 are $0.82 for a stamped one-ounce letter, $1.11 for 2 ounces, $1.40 for 3 ounces and $1.69 for 3.5 ounces. The additional-ounce amount is $0.29 and the letter nonmachinable surcharge is $0.49.
Where to buy postage stamps for your wedding →
Planning Your Wedding Stamp Purchase
Once you know your total stamp count, the question becomes: how should you buy them? Here is a practical breakdown of common quantities and costs.
For weddings with 100 or more guest households, buying rolls of 100 is more convenient than counting out individual books. A roll of 100 Forever stamps has a face value of $82.00 at today’s price.
Full details on the 2026 Forever stamp price increase →
Frequently Asked Questions
How many stamps do I need for wedding invitations?
For a standard rectangular wedding invitation envelope weighing 1 ounce or less, you need one Forever stamp — currently $0.82. However, you also need a separate stamp for the pre-addressed RSVP return envelope you include inside. So plan for two stamps per guest household for the mailing alone, plus additional stamps for thank-you cards later. If you have 100 guest households, expect to need around 300 stamps total across the full wedding cycle.
Do Forever stamps expire?
No — Forever stamps never expire. A Forever stamp purchased at any price still covers 1 ounce of First-Class Mail regardless of when you use it. This makes them ideal for wedding planning: you can buy stamps months in advance at today’s $0.82 price and use them even after rates increase to $0.82 on July 12, 2026.
What if my wedding invitation is in a square envelope?
Square envelopes (such as 5×5 or 6×6 inches) cannot be processed through USPS sorting machines and require a non-machinable surcharge. The total postage for a square 1-ounce letter is approximately $1.31, not $0.82. A single Forever stamp will not cover it. You will need to add extra ounce stamps or use a combination of stamps that totals $1.31 or more.
What is the current USPS one-ounce letter rate?
Where is the best place to buy stamps for a wedding?
You can buy Forever stamps at USPS.com, your local post office, or authorized retailers. Costco sells rolls of 100 for $77.75 (members only). Online stamp stores may offer 10–15% off face value on unused valid Forever stamps. For a typical wedding requiring 200–300 stamps, comparing prices across a few sources can save $20–50 or more.
Final Thought: Plan Your Postage Before Prices Rise
Wedding invitations are one of the most predictable stamp purchases you will ever make. You know your guest list months in advance, you know how many stamps each household needs, and you know the current price. That makes it straightforward to buy the right quantity — whether that is a few books of 20 for a small gathering or multiple rolls of 100 for a larger event.
Browse Love stamps for wedding invitations →
Learn more about buying Forever stamps for less →
Sources and update note
Use the linked primary record for the exact issue, rule or current condition. Prices, availability and platform features can change and should be checked at the time of use.