Our mugs are all designed to hold approx. 12 oz of liquid. However, the straight mugs and the flare mugs tend to hold more liquid (approx. 14-15 oz). Also, the handmade nature of our work means that each mug will be slightly different in terms of the exact volume that it holds. While many of our customers are OK with these natural variations, if you require your drinking vessel to hold a very specific volume of liquid, please think twice before purchasing.