Recently I was asked why square envelopes require extra postage and was happy to know the answer. Most of our mail is sorted by machines these days which makes mailing more efficient. Square envelopes put a kink in this efficiency because the address could end up vertical when going through the sorter, which keeps the scanners from reading the address. Square envelopes are most likely sorted by hand, which costs more money, therefore making them more expensive to mail. This is important to keep in mind especially when planning out wedding invitations when you'll likely be sending out a large number of envelopes. The extra postage can add up to a lot when you are on a budget. Make sure you consider this important fact when choosing to send a square invitation for any event.
In addition to shape requirements, there are size and weight requirements for envelopes, large envelopes and postcards. Your local post office or the United States Postal Service
website can help you determine the correct postage for your letters and packages.
With any wedding invitation, it is recommended that you take one complete invitation to be weighed by the post office to ensure that you are within the weight requirements for postage before you purchase all of your stamps. You'll want to make sure you apply the correct postage to avoid delivery delays, returns or having to plop another stamp on your envelope. A little bit of planning can save you a big headache AND from resorting to online invitations (more on that shortly!). Happy Mailing!