STANDARD POSTCARDS 4×6
Standard Postcards are a great source to advertise or keep in touch. The USPS dictates size for mail in the United States based on the requirements. The small size is 3.5 inches by 5 inches. The largest size is 4.25 inches by 6 inches. The USPS also requires the dimensions be between 0.007 inch and 0.016 inch thick. Cards under the smallest size or weight are not mailable.
They are an inexpensive way to get an immediate message to customers. When they arrive in the mail, there’s the message — no envelope to open! First-Class Mail cards are a great value too. You pay a low price and get all the benefits, like forwarding and return that come with First-Class Mail.
You may think that your mail piece is a “card,” because it is a single sheet of paper. But to qualify for mailing at the First-Class Mail price, it must be set to regular.