One of the most important, yet overlooked part of wedding invitations, is postage. Calculating the right amount of postage that will be needed to mail the invitations to your guests, can be quite tricky and can lead to unexpected surprises.
It is also important to consider that postage pricing is constantly changing. The only stamps that retain their value, are the so called “forever stamps”. So a forever stamp that you might have bought 10 years ago for $0.35, today can be used for a 1oz letter, valued at 0.68c in 2024 (please check current usps prices here https://store.usps.com/store/results/stamps/_/N-9y93lv)
As a rule of thumb, it’s best to take one of your fully assembled wedding invitations to the post office to have them weigh it for you and advise you on the correct postage amount

While most of the mail that we receive every day, can be sent with a simple “forever stamp”, most wedding invitations will require more postage. A forever stamp will be enough to mail a piece up to 1 ounce in weight, and does not exceed 11.5 inch x 6.125 inch.


Most of our wedding invitations do respect the size restrictions, but most of the times, once including insert card and response card, end up weighing more than 1 ounce, at which point, will require more postage, based on the weight.

  • A letter of 1 ounce – 1 Domestic Forever Stamp costs 68 cents
  • A letter of 2 ounces – 1 Domestic Forever Stamp and 1 additional ounce stamp at 24 cents – costs $0.92
  • A letter weighing 3 ounces – 1 Domestic Forever Stamp and 2 additional 24-cent stamps – costs $1.16
  • A letter weighing 3.5 ounces – 1 Domestic Forever Stamp and 3 additional 24-cent stamps – costs $1.40

Note: Once your envelope exceeds the 3.5-ounce weight limit, you will need to look at rates for “flats,” which are large envelopes for mailings from 3.5-13 ounces.

odd size, squares and non machineable stamps

The prices discussed above are for envelopes that can mail flat, do not exceed 1/4 inch in thickness, and do not exceed 11.5 inch x 6.125 inch in size. But what happens when we have one of the following:

  • square envelopes or envelopes over 6.125 inch tall
  • items that are too rigid such as pocket folders or multiple layered invitations
  • items that don’t bend easily such as folder or folios
  • items that have clasps, strings, was seals, ribbons with knots and other enclosures

In most of the above cases, these envelopes will need to ship as “flats”. Flats are those letters that are either too rigid, too thick or too wide/big to fit the small slit on the photo above. The cost for these in 2024 is as below

  • A Flat of 1 ounce – $1.39
  • A Flat of 2 ounces – $1.63
  • A Flat of 3 ounces – $1.87
  • (and so on in increment of $0.24 per ounce up to 13oz)

What is a Non-Machinable Stamp?

A non-machinable stamp is a type of postage stamp that is designed for letters that are “non-machinable”. Non-machinable mails are letters that are not able to be processed by postal machines. These letters may be irregular in size or shape, or they may be too thick, rigid, or have unusual contents. Given that non-machinable mail has to be hand processed, USPS requires extra postage to take this extra work into account. As of MARCH 2024 the cost for a non-machinable surcharge is 44 cents. So if you are sending out a letter that weighs one ounce, USPS will require $1.12 (it’s the 68 cent postage rate for a 1 ounce letter plus the 44 cents for the non-machinable surcharge).

Non-machinable stamps are larger than regular stamps and feature a specific design to indicate that they are intended for non-machinable items. They usually say “non-machinable” instead of “forever” to indicate that they are worth enough in postage to cover the 1 ounce standard letter rate plus the non-machinable surcharge.

custom postage

Companies such as Minted and Zazzle previously sold 2,000 different wedding-themed stamps or you could even create your own custom postage stamps! Sadly, the USPS ended their custom postage program in June of 2020 and there are no companies left that offer custom postage stamps.

vintage stamps

Vintage stamps add SO much charm and personality to a wedding invitation suite. Vintage stamps are simply older stamps that are usually curated in “sets” to match the wedding vibe or the couple’s personalities. The cost of vintage stamps can get high pretty quickly, for a curated set of 4 or 5 pieces totaling the value needed for a 2oz invitation ($0.92) could cost between $4 and $8 depending on the supplier and the stamps chosen. One of the most important things when it comes to vintage stamps, is ensuring that the supplier is a verified supplier, as there is never a shortage of scammers and fake stamps sellers on the internet. Our go to favorites are VerdeStudio on Etsy, LittlePostageHouse on Etsy and EdelweissPost.

an end note

At the end of the day, it is known that your invitations will have to go through the mail system. Using the right amount of postage will definitely help your invitations getting to your guests safely, but sometimes a few extra steps to ensure that your envelopes arrive in good conditions are needed. A special note needs to be given for invitations that feature wax seals and ribbons, and envelopes that are too thick or too rigid. We always recommend using a double envelope with these choices, along with the correct amount of postage needed.

To take a closer look on how these workhorses function, take a look at this video. The speed these machines have is absolutely a factor when it comes to maintain your invitations in pristine condition, some of the thicker invitations definitely cannot go through some of those twists and turns, and it is very important to consider this when choosing your invitations and when choosing your postage.