Drywall Estimator

For calculation purposes:
a window is defined as a double hung unit measuring 36"x52"
an interior door is defined as an opening 30" wide and 80" tall
an exterior door is defined as an opeing 36" wide and 80" tall

Enter WIDTH of room:  FEET
Enter LENGTH of room:  FEET
Enter HEIGHT of walls:  FEET
Size of drywall sheet: ft. X ft.
Number of Windows:
Number of interior doorways:
Number exterior doorways:
Drywall on Ceiling?  Yes   No