Measure the length and width of the area in feet
Multiply length × width to get square feet
Choose the mulch depth in inches
Convert depth to feet by dividing inches by 12
Multiply square feet × depth in feet to get cubic feet
Divide cubic feet by 27 to get cubic yards
Use 1 cubic yard of mulch to cover about 324 square feet at 1 inch deep
Use 1 cubic yard of mulch to cover about 108 square feet at 3 inches deep
Add extra mulch for settling and uneven ground
Round up to the nearest bag or cubic yard