It takes approximately 13 1/3 small apples, 7 1/2 medium apples or 5 large apples to make 10 cups of sliced apples. This number varies slightly depending on how thin the apples are sliced. Thinner slices fit tighter in a measuring cup, so it can take more apples to make 10 cups than with thicker slices.
The estimated number of apples is based on a diameter of 2 1/4 inches for small apples, 2 3/4 inches for medium apples, and 3 3/4 inches for large apples. Size is likely to vary in a bin of apples in a grocery store, so use the average apple size in your calculation.
To avoid making an extra trip to the store for more apples, it helps to buy more than you need. Round up to the nearest whole number of apples, or add an extra apple of each size to your cart to compensate.
An apple loses approximately a third of its weight when the peel and core are removed. This translates to roughly a 65 percent yield from whole apples. Expect to get about 3 cups of peeled, sliced apples per pound of whole apples. When purchasing apples by the pound instead of by count, expect to purchase 31/3 pounds of apples to yield 10 cups of sliced apples.