How much mulch do I need?
Cubic feet = length (ft) × width (ft) × depth (in) ÷ 12
Bags = cubic feet ÷ bag size · Cubic yards = cubic feet ÷ 27
Example: a 20 × 5 ft bed, 3 inches deep
20 × 5 × 3 ÷ 12 = 25 cubic feet, or 0.93 cubic yards. In 2 cubic foot bags that's 13 bags, about $52 at $4 a bag. Bulk at $40 a yard would cost about $37 before delivery.
Bags or bulk?
A cubic yard is 13.5 two-cubic-foot bags. Bulk is usually cheaper per yard, but delivery fees often make bags the better deal below two or three yards.
Frequently asked questions
How deep should mulch be?
Two to three inches for most beds. Thicker layers suppress weeds better, but keep mulch a few inches away from tree trunks and plant stems.
How many square feet does a bag of mulch cover?
A 2 cubic foot bag covers about 8 square feet at 3 inches deep, or 12 square feet at 2 inches.
Last reviewed: 2026-10-31