$1.00 Stamps for Large Envelopes (1 oz)
In 2021 you'll need a $1.00 stamp to mail a 1 oz first-class "large envelope" letter.
Letters are considered "large envelopes" or "flats" if they measure greater than 6-1/8 inches high OR 11-1/2 inches long OR 1/4 inch thick.
There are no stamps with a face value for this specific rate. If you want to use stamps you'll need to combine stamps with a smaller face value to add up to $1.00 or greater.
You can determine if your wedding invitation is a standard letter or a large envelope by using our postage calculator, but be sure to double-check the weight of your invitations with your local USPS post office before ordering postage online.