Enter bed length, width and the depth of mulch wanted to get cubic yards for bulk delivery and the bag count for bagged mulch.
Mulch volume is bed area multiplied by depth. Two to four inches is the useful range: thinner than 2 inches weeds push through quickly, and much deeper than 4 inches can keep water from reaching roots and can sour around plant stems. One cubic yard covers about 108 sq ft at 3 inches deep, and bulk delivery usually works out cheaper than bags once a job passes roughly 3 cubic yards — though bags are easier to move to a back garden a few at a time.
How deep should mulch be? Three inches is the common recommendation for beds: enough to suppress weeds and hold moisture without smothering roots. Keep mulch a few inches away from trunks and stems.
How many 2 cu ft bags are in a cubic yard? A cubic yard is 27 cubic feet, so 13.5 — in practice 14 — bags of 2 cu ft equal one cubic yard.