We get asked this question a lot and basically there are five categories or groupings of flask sizes. As a rule of thumb: smaller flasks are generally used by woman or for activities where you will not be out for long periods of time. The 4-5 ounce size is also more typically used by women and thought of as a personal flask. The 6 ounces flask is a common size and is used by a man as a personal flask and often used for sharing with a friend when carried by a woman. The 8oz flask is more typically used by a man if planned for solo consumption, though it contains enough to enable sharing. It can also be used singularly by men or women for all day consumption. The larger than 8oz flasks are suitable for sharing amongst friends.
The size flask that you decide to purchase is a personal decision based on how much you drink, over what period of time you will need to drink, if you have access to refill your flask and whether or not you plan to be sharing. We recommend having multiple sizes on hand so that you always have the perfect flask for whatever your needs may be.
<3oz Flask: 2 Shots or Less
4-5oz Flask: Little less than 3 Shots
6 oz Flask: 4 Shots
7-8oz Flask: Little less than 6 shots
> 8oz Flask: Typically 6 shots or more.
NOTE: A shot is the equivalent of one and ½ ounces.