– Consider the size and shape of your invitations. Whether your invites are considered postcards, letters or large envelopes will have a major impact on your postage budget. The United States Postal Service considers postcards to have dimensions between 5 x 3.5 and 6 x 4.25 inches. A letter is considered to be between 5.5 x 3.5 and 11.5 x 6.125 inches. Note that square, round and extra-heavy invitations will also be charged a heftier postage fee.
– Remember this formula from the USPS: Shape + speed + cost = service. This means that the amount of time you want to allow for invitation delivery will impact your postage costs. For wedding invites, you’ll likely want to chose Express, Priority or First-Class mail.
– Don’t forget about your international guests! Postage rates will vary based on country, with rates to Western European countries currently averaging about 95 cents for a 1-ounce letter.