Some of the mugs here have a description that gives 15 oz as the capacity. I measure it as a USABLE capacity of 14 oz. If you fill it to the brim (15 oz) you have the potential to easily spill (hot tea?).
The graphic design is good. The size and physical design is also good and fits nicely in my hand. I wish the walls were just a bit thicker. This is an issue with most mugs (thin walls conduct the heat of the liquid inside too easily).