First off, let me mention that this is only a basic guideline and for best sizing, always measure the area where you want the design as there are many factors that go into picking the best size. For instance, a tank top would very possibly need a different size than a regular unisex T-shirt. Also some people just like the design to be larger than other people’s preferences so for best results, measure! Also remember that our subs are measured from the longest side so the design may be 10 inches long but only 5 inches wide or 10 inches wide but only 5 inches long, it just depends on the size ratio of each particular design. Most of the time, the sizing still works out as suggested because you do not want a design to hang super long or be too wide to fit but it is another thing to consider when choosing your size.
General Guidelines
Infant shirts, Pocket Designs, Can Coolers, Coffee Mugs - 3 inch
Toddler - 6 inch
Youth - 8 inch
Adult S-L - 10 inch
XL up and Back of Shirts - 12 inch