There is no set standard on what size patches should be used as each hat size is different from other hats, but the best overall size for a patch on a hat is anywhere between 2 to 2.25 inches tall. The width will be proportional to the overall shape of your design. To calculate a patch size you need to know the largest width of your desired patches so that we have an accurate calculation: add up the highest point on both sides then divide by two! This will give us our final patch size! Another option to using a patch is with direct embroidery where you can go up to 5" wide by 3" tall.