The term postcard seems simple enough. It’s that thing you always receive while friends are visiting foreign exotic places. It’s what fills your mailbox during political season. It’s what tells of great sales or new places to try for dinner. But when learning postal terminology, a postcard is not always a postcard.
The United States Post Office has a special designation within called a postcard, that can allow first class mail to be sent at discounted rates. These postcards will mail for about 75% of the cost of a first class letter, so they stand to save you a sizable amount of money on bulk mailing when used correctly.
All mail pieces must be at least 5 inches long by 3.5 inches tall. A first class postcard must not exceed 6 inches long by 4.25 inches tall.
As long as the card is between these two sizes and meets all the other requirements of a letter, then it can receive the postage savings. (See our post about "letter" rates for more detail on what makes a letter.)
Many people think mailing this smaller card will always save them postage. However, this is only true when sending first class mail, which has higher postage rates than standard mail.
With standard mail, the postage rate for a post card stays the same all the way up to 11.5 inches wide by 6.125 inches tall allowing nice large cards to be sent out at very affordable rates.