Unit check
Area and depth must be compatible. For square feet, convert inches of depth to feet before multiplying.
Example
A 200 square foot bed with 3 inches of mulch uses a depth of 0.25 feet. The base volume is 200 x 0.25 = 50 cubic feet; with 5% waste, plan for about 52.5 cubic feet before converting to bags or bulk units.
Common mistakes
Do not enter 3 inches as 3 feet. Also account for irregular beds, tree rings and edging if your measured area is only an approximation.
Limitations
Real ordering depends on bag size, settling, moisture and whether the bed has irregular edges.
Last reviewed: 2026-05-17