To figure your quantity:
Take your square foot and divide by 9, then divide again by 36, and times by the number of inches deep. This will equal the number of cubic yards.
Sq. Ft. / 9 = _______,
______ / 36 = _______,
______ x depth = cubic yards.
Or
One cubic yard will cover:
324 sq.ft. @ 1" deep
162 sq.ft. @ 2" deep
108 sq.ft. @ 3" deep
81 sq.ft. @ 4" deep
65 sq.ft. @ 5" deep
or use this calculator: