Before you start to calculate 221 Cups, you should know the conversion rate between Cups and Cubic Yard.
The rate is 3.0E-19 and the math equation is 221 X 3.0E-19 = 6.63E-17 .
Quick conversion chart of Cups to Cubic Yards
1 Cup to Cubic Yard = 3.0E-19 Cubic Yard5 Cup to Cubic Yard = 1.5E-18 Cubic Yard10 Cup to Cubic Yard = 3.0E-18 Cubic Yard20 Cup to Cubic Yard = 6.0E-18 Cubic Yard30 Cup to Cubic Yard = 9.0E-18 Cubic Yard40 Cup to Cubic Yard = 1.2E-17 Cubic Yard50 Cup to Cubic Yard = 1.5E-17 Cubic Yard75 Cup to Cubic Yard = 2.25E-17 Cubic Yard100 Cup to Cubic Yard = 3.0E-17 Cubic Yard