Mulch & Soil Calculator
Calculate the volume of mulch, soil or compost needed to cover an area.
Results update as you type.
About this calculator
A mulch calculator multiplies the area of a garden bed by the depth you want to spread to give the volume of mulch, topsoil or compost required — in cubic yards or cubic metres — plus an estimate of how many standard bags that is. Deeper layers and larger beds need proportionally more.
Frequently asked questions
How do I calculate cubic yards of mulch?
Multiply the area in square feet by the depth in feet (inches ÷ 12), then divide by 27 to convert cubic feet to cubic yards. A 20×10 ft bed at 3 in deep is 200 × 0.25 = 50 cu ft, or about 1.85 cubic yards.
How deep should mulch be?
Two to three inches (about 5–8 cm) is typical for beds — enough to suppress weeds and hold moisture without smothering plants. Deeper is fine for paths but keep mulch off plant stems and trunks.
Results are estimates for general guidance only, not financial, medical or tax advice.