How this mulch calculator works
Mulch is sold by volume, so the math is simple: bed area multiplied by depth gives cubic feet or liters, converted to cubic yards or cubic meters — the units bulk suppliers use. Bagged mulch most commonly comes in 2 cubic foot bags in North America and 50 liter bags in Europe. For irregular beds, break the shape into rectangles, calculate each and add them together.
How deep should mulch be?
Two to three inches (5–7.5 cm) is the sweet spot for most beds — enough to suppress weeds and retain moisture without suffocating roots. Use 2 inches around perennials and shallow-rooted shrubs, 3 inches for trees and open beds, and never pile mulch against trunks or stems. A thin 1-inch (2.5 cm) top-up is enough when refreshing existing mulch.
Bulk or bagged?
Above roughly one cubic yard (0.75 m³), bulk delivery is almost always cheaper per unit — often half the price of bags. Bags win for small jobs, tight access, or when you need to move material through a house. Bulk mulch also tends to be fresher, but you'll need a spot for the pile and a wheelbarrow afternoon.
Coverage quick reference
One cubic yard covers 108 square feet at 3 inches deep, 162 square feet at 2 inches, or 324 square feet at 1 inch. In metric, one cubic meter covers about 13 m² at 7.5 cm deep or 20 m² at 5 cm. A single 50 L bag covers 1 m² at 5 cm depth.