The prints size on the front of hoodies is limited by the space bettween pocket and neck seem. The spacing varies from size to size. This is because all the pocket stays the same size while the hoodie gets larger.

For example Jerzees Brand 996 hoodies have the following max printable areas:

Youth Small = 6" Wide X 4" High
Youth Medium = 10" Wide X 8" High
Youth Large = 13" Wide X 10" High
Youth X-Large = 13" Wide X 13.5" High

Adult Small = 13" Wide X 8.5" High
Adult Medium = 13" Wide X 10" High
Adult Large = 13" Wide X 12" High
Adult X-Large = 13" Wide X 14" High
Adult 2X-Large = 13" Wide X 15" High

As you can see if you want 1 imprint size for all the hoodies in your order and that order includes Youth Smalls then the art can be no bigger than 9" Wide X 4" High. That size may not be desirable on a size Adult Large.

Please be mindful of this when designing the graphics and placing the order.