The Best Standard Direct Mail Postcard Sizes 2023. Web postcard size in inches: Between 5” and 6” width.
Standard postcards are usually made of paper, are between 5 to 6 long. Other standard postcard sizes include 3” x 4”, 4.25” x 5.5”, 4.25” x 6” and 5” x 7”. Web if you want to create a postcard of your own, you need to know what sizes are commonly used.
