Landscaping
mulch & soil volumeMulch / Soil Volume
Cubic yards of mulch, soil, or gravel needed for a bed area, based on length, width, and fill depth.
How to Use the Mulch & Soil Volume Calculator
Enter the length and width of your bed or planting area in feet, and your desired depth in inches. The calculator returns the volume in both cubic feet and cubic yards — most bulk suppliers sell mulch, soil, and gravel by the cubic yard.
How the Calculation Works
Volume = length × width × depth, with depth converted from inches to feet by dividing by 12. The result in cubic feet is then divided by 27 (the number of cubic feet in a cubic yard) to give the figure most suppliers quote and price by.
Example Calculation
A 20×8 ft bed at 3 inches of mulch depth: volume = 20 × 8 × (3 ÷ 12) = 40 cubic feet, or about 1.48 cubic yards.
Frequently Asked Questions
How deep should mulch be?
2–3 inches is the typical recommended depth for most mulch types — enough to suppress weeds and retain moisture without smothering plant roots or trapping excess moisture against stems.
Does this work for soil and gravel too?
Yes — the volume math is identical regardless of material. Just enter your desired depth for topsoil, compost, or gravel fill the same way you would for mulch.
How many bags of mulch equal a cubic yard?
Bagged mulch is commonly sold in 2 cubic foot bags, so it takes about 13.5 bags to equal one cubic yard (27 ÷ 2). For large areas, bulk delivery by the yard is usually more cost-effective than buying bags.