Almost all invitations will cost more than 42 cents to mail. If it’s square, if it’s thicker, if it’s more than 6-1/8 inches on two sides, it will cost at least 20 cents more. The Post Office increased rates about 6 months back, and finally sorted out the increases.
If any of your wedding stationery (mailable) has the slightest bump, add 20 cents.
So, if you are trying to spruce up a really simple invitation by adding a bow, a tie, a pressed flower, anything that adds a bump, add 20 cents per.
Don’t get your mail returned. Don’t get caught by surprise. Never mail out your invitations without getting a finished piece weighed at your local post office.
If you get frustrated with the lack of aesthetics when choosing stamps for the extra postage, check out the fun you can have making your own stamps with Zazzle.