For adult shirts, even with a size scale of Adult S through Adult 5XL, 11" by 11" or larger is recommended.
However, with DTF transfers you are able to modify the sizes as you like and still retain the bulk discount pricing on the whole order.
If you prefer to modify the design size based on shirt size, we recommend the following:
Adult Small through 2XL: 11" by 11" or larger
Adult 3XL through 5XL: 12" by 14" or larger