By observing the minimum size requirement for U.S. Postal Service first-class mail, it is possible to print four customized postcards from one sheet of paper. The minimum size requirement is 3.5 by 5 inches. Postcards must be printed on card stock with a thickness in the range of .007 to .16 inches. Standard postcard size is 4 by 6 inches, with 4 1/4 by 6 inches as the maximum size for postcard rate postage. Any size larger than 4 1/4 by 6 inches will be charged at letter rate.
Design your postcard. Set parameters of 3 3/4 by 5 inches in the design program of your choice. If you are using a photo-editing or design program, create your postcard and flatten the image so that it is in JPG format. If you are using a text-editing program, creating four identical postcards on one page will be easier if you restrict your design to one text field.
Divide your page into equal fourths. Set 1/4-inch page margins around the outside: top, bottom, right and left sides. Set 1/2-inch gutter margins lengthwise and by width to create a 1/4-inch margin on all sides of your postcard design. This step is necessary unless you are having your cards printed commercially, because home and business printers do not print all the way to the outer edge of the paper.
Copy and paste the postcard design into each section of your postcard page template.
Print the page. If you have designed the reverse side of your postcard to include a place for postage, return address and recipient address, place your printed page back into the paper tray to print the reverse side.
Place the sheet on a cutting board, and slice down the middle lengthwise. Cut each half in the middle along its width.