One medium-sized banana, typically about 7 to 8 inch long, yield approximately 1 cup of sliced banana or about 3 quarter cup of mashed banana.

This measurement can vary slightly depending on the size and ripeness of the banana.

If you need a precise amount for a recipe, it's best to measure the banana after slicing or mashing it.

For reference, a small banana about 6 inch long will yield slightly less than 1 cup when sliced and a large banana about 9 inches long or more will yield about a bit more than 1 cup.