Embroidery can be as small as 1/2" x 1/2", but you must consider the complexity of the design. It must be sufficiently large for the details to be visible and embroider clearly.

We can embroider a design as large as 16" x 12".

The main factor you should consider is the placement on the garment. In general, for placement on a pocket or the chest of a shirt the maximum size should be about 4". Embroidery on aprons can be larger.