A Postcard is Not a Postcard
Most of us think a postcard design is printed advertising on thick card stock. It could range in size from 4″ x 6″ to 5½” x 8½” or 6″ x 9.” Some believe that these cards can all be mailed at first-class card rates or standard rates and the postage cost would be the same for each. Not true; a postcard cannot exceed 4¼” x 6.” These postcards have a special first-class card rate currently at $0.33 cents (retail). Anything larger is considered a letter and would mail at the letter rate, which costs more than the card rate.
Minimum: 5″ long, 3½” inches high, and 0.007″ thick.
Maximum: 6″ long, 4¼” high, and 0.016″ thick
Postage costs for each first-class card range from $0.33 per card (retail) to as low as $.234 per card depending on the density of your mailing list. In order to achieve a rate per card less that $0.33 per piece, you would need to mail a minimum of 500 pieces and have your mailing list postal presorted.