Wedding invitation postage is one of the most overlooked logistics in the mailing process — until 200 envelopes come back as undeliverable or a couple discovers at the post office that they’ve bought the wrong stamps.
The core issue: most wedding invitations don’t qualify for a standard first-class letter stamp. They’re heavier, sometimes larger, and often irregularly shaped. Paying standard postage on a non-standard invitation suite means a significant percentage will be returned or require recipients to pay postage due to receive them.
This guide covers how to calculate the right postage for US and Canadian wedding invitations, plus everything you need to know before you buy stamps or queue at the post office.
Why Wedding Invitations Usually Need Extra Postage
A standard first-class letter in the US (under 1 oz, standard rectangular size) costs $0.73 as of early 2026. Most wedding invitation suites exceed this threshold because of:
Weight. A typical wedding invitation suite — outer envelope, invitation card, inner envelope, RSVP card, and RSVP envelope — weighs between 1.5 and 3 oz. Every additional ounce above 1 oz adds $0.24 in US postage.
Size. Non-standard sized envelopes (square, oversized, or unusually shaped) trigger a non-machineable surcharge from USPS — currently $0.40 per piece. Square invitations almost always trigger this surcharge.
Thickness and rigidity. Very rigid envelopes (with acrylic, vellum, or board inserts) may be classified as “non-machineable” regardless of size, adding the same surcharge.
Wax seals. A wax seal on the outer envelope adds slight thickness and can jam postal machinery. Many couples hand-cancel wax-sealed envelopes at the post office to avoid damage — this is typically free if you bring them in unsealed and ask.
USPS Postage Rates for Wedding Invitations (2026)
| Weight | Standard rectangular | Non-standard / square |
|---|---|---|
| Up to 1 oz | $0.73 | $1.13 |
| Up to 2 oz | $0.97 | $1.37 |
| Up to 3 oz | $1.21 | $1.61 |
| Up to 3.5 oz | $1.45 | $1.85 |
Important: These rates are for first-class mail. Postage rates are updated periodically; verify current rates at usps.com before purchasing stamps.
Most wedding invitations fall in the 2–3 oz range. If your suite includes a square envelope, budget for the non-standard surcharge.
How to Calculate Your Actual Postage
Step 1: Assemble one complete invitation suite — exactly as it will be mailed. Include every insert, the inner envelope, the RSVP card, and the RSVP return envelope.
Step 2: Weigh it at a post office. Don’t use a kitchen scale for this if you can avoid it — postal scales are more accurate and the post office can give you the exact rate on the spot. Bring the assembled suite before you’ve sealed anything.
Step 3: Note the envelope dimensions. Measure the outer envelope. If it exceeds 11.5″ × 6.125″ or is square, you’ll pay the non-standard surcharge.
Step 4: Multiply by quantity + buffer. Add 10–15 extra to your planned invitation count for addressing errors, late additions, or damaged envelopes.
The free Wedding Invitation Postage Calculator walks through this calculation with your specific inputs — weight, size, and quantity — and gives you a total postage cost in one step.
Don’t Forget Return Postage
Every RSVP card you include needs a pre-stamped return envelope if you expect guests to use them. The RSVP envelope is typically smaller and lighter than the outer invitation envelope — usually qualifying for a standard first-class stamp at $0.73.
For 150 invitations, RSVP return postage alone is approximately $110 at current rates. Add this to your total postage budget before you shop for stamps.
Canada Post Rates (2026)
Canadian wedding invitation postage follows a similar logic but uses Canada Post’s domestic letter pricing.
| Weight | Domestic rate |
|---|---|
| Up to 30g (about 1 oz) | $1.15 |
| Up to 50g (about 1.75 oz) | $1.94 |
| Up to 100g (about 3.5 oz) | $2.71 |
Non-standard sizes (square envelopes, oversized) may also attract surcharges. Check with Canada Post at canadapost-postescanada.ca for current rates and size requirements.
For invitations being mailed internationally between the US and Canada — common for weddings with cross-border guest lists — use the US international letter rate for guests in Canada, and vice versa. These rates are significantly higher per piece.
Vintage Stamps and Beautiful Options
Many couples want their wedding invitation postage to match the aesthetic of the suite itself. A few options:
USPS Forever stamps with custom designs. USPS allows custom photo stamps through an approved vendor program. These are real postage stamps printed with your chosen image — a meaningful option for detail-oriented couples.
Vintage or collectible stamps. USPS and Canada Post sell older commemorative stamps at face value through their philatelic programs. Estate sale shops and online philatelic vendors also sell vintage stamps in bulk — often at face value or slightly above. Using multiple small-denomination stamps to make the correct total is entirely valid and often beautiful.
Hand-cancelling. If you’d prefer your beautiful stamps not to be machine-cancelled (which can obscure the design), ask your post office to hand-cancel the envelopes. This is a free service but must be requested and may require a visit during off-peak hours.
Mailing Timeline
6–8 weeks before the wedding: Standard “save the date” cards, if using them, go out well before formal invitations.
8–12 weeks before the wedding: Formal invitations should be mailed. For destination weddings or events requiring significant guest travel, 12 weeks is the minimum.
RSVP deadline: Set this 3–4 weeks before the wedding — enough time to finalise catering numbers and seating.
Allow 5–7 business days for domestic delivery in the US and Canada. Invitations to international addresses should be mailed 2–3 weeks earlier to account for international transit times.
FAQ: Wedding Invitation Postage
Can I just use two regular stamps? For a 2 oz invite using a standard rectangular envelope: two Forever stamps ($1.46 total) would slightly overpay compared to exact postage, but it works. The problem is a square envelope or anything that triggers the non-machineable surcharge — two Forever stamps won’t cover it.
What happens if I underpay postage? The post office returns the envelope to the sender (you) or delivers it to the recipient with “postage due” — meaning the recipient must pay the remaining amount to receive it. Neither is a good outcome for a wedding invitation.
Do I need to go to the post office or can I buy stamps online? You can buy stamps at usps.com or canadapost-postescanada.ca and have them delivered. However, to weigh your assembled suite and confirm the exact rate, a post office visit for the test run is worth the trip.
What if guests’ invitations look different (different inserts for different tiers)? Weigh each version separately. If some guests are receiving additional inserts (accommodation cards, menu selections, additional enclosures), those versions will weigh more and may require different postage.
Can the post office process wax-sealed envelopes? Yes, but they may be damaged in sorting machinery. Bringing them in unsealed and asking for hand-cancellation is the safest approach.
Should I include a stamp on the RSVP envelope? Yes if you want a strong response rate. Guests who have to find and affix a stamp will RSVP at significantly lower rates than guests with a pre-stamped envelope. Include the stamp.
Test One Before You Buy a Hundred
The single most important piece of advice in wedding invitation postage: bring one complete, assembled invitation suite to the post office before you buy stamps for all of them. A 15-minute visit to the counter will tell you exactly what rate applies and what stamps to buy.
Buying 200 stamps before confirming the rate is the most common (and most avoidable) invitation postage mistake.
