Get the dimensions of the container in feet, calculate the volume of the container in cubic feet. When you have this result you can calculate its capacity in quarts by remembering that there are 6.25 gallons in one cubic foot, there are four quarts in a gallon so there are 6.25 x 4 quarts in a cubic foot, 25 quarts. Simply multiply the volume in cubic feet by 25 and you will have your answer