judy - from lisbon, OH
A standard 16.5 ounce box of cake mix makes about 4-1/2 cups of cake batter; of course this varies by brand. Below I've included a link to the Wilton baking chart. This chart tells you how many cups of batter is needed for each type of pan and an approximate bake time; remember baking times vary by oven.
It is best to measure the amount of batter your favorite cake mix makes and use the chart to determine how many boxes to use.