Two experiments were performed to examine the effects of cup size, gender, age, and parameters of sipping (cup vs. straw and sequence) on sip volume. Increasing the size of the vessel from 150 to 600 ml increased the volume of a sip by about 15%. Males took larger sips and had significantly larger maximum oral capacities than females. However, in a second group of taller females and shorter males, the difference in sip size between genders was minimized. A second experiment examined sip size from a cup and straw drinking, the effects of sequential sipping (one to five sips), personal characteristics (height, weight), age, and gender on sip volume. Height was a good predictor of individual differences in sip volume. Cup drinking produced larger sip volumes than straw drinking, but only in a group of adults and not in an elderly group. Volume per sip decreased across sips. A reasonable guide for cup sipping is about 25 ml per sip for males and 20 ml for females. However, this rule should be modified as a function of cup size, straw sipping, and sequential sipping.