Mulch Coverage Calculator
Turn a bed area and mulch depth into cubic feet, cubic yards and the exact number of bags to buy.
How it works
Cubic feet = area(ft²) × depth(ft) · depth(ft) = depth(in) ÷ 12 · Cubic yards = ft³ ÷ 27 · Bags = ⌈ft³ ÷ bag size⌉
Mulch volume is the bed area multiplied by the depth in feet (inches ÷ 12). A 2–3 inch layer is the sweet spot for most beds: deep enough to suppress weeds and hold moisture, shallow enough to let water and air reach the roots. One cubic yard of bulk mulch covers about 108 ft² at 3 inches, so bulk usually wins once you pass roughly 10 bags.
Worked example
A 200 ft² bed at 3 inches deep: 200 × (3 ÷ 12) = 50 ft³, or 1.85 yd³. At 2 ft³ per bag that is ⌈50 ÷ 2⌉ = 25 bags; at $4 each, about $100.
Frequently asked questions
How deep should mulch be?
Two to three inches is ideal for most ornamental beds. Go slightly deeper (3–4 in) for heavy weed suppression, but keep mulch a few inches away from stems and trunks to avoid rot.
How much area does a yard of mulch cover?
One cubic yard (27 ft³) covers about 162 ft² at 2 inches, 108 ft² at 3 inches, or 81 ft² at 4 inches deep.
Bags or bulk?
Bags are convenient and mess-free for small beds. Bulk delivery is much cheaper per cubic yard once you need roughly a yard (about 13–14 two-cubic-foot bags) or more.
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This calculator is for educational purposes. Double-check important results before acting on them.