How Much Mulch Do I Need?
The amount of mulch you need depends on the square footage of your bed and the finished depth you want. Once those two measurements are known, the calculation is simple.
Last updated October 6, 2026 · Written for practical home-project planning.
Start with square footage
For a rectangular bed, multiply length by width. For example, a 20 × 10 ft bed has 200 sq ft. Irregular beds should be divided into smaller measurable areas.
Choose a finished depth
A planning range of 2–4 inches is common for many landscape beds, but the correct depth depends on the material and planting situation. Avoid piling mulch against tree trunks or plant crowns.
Convert the depth to cubic yards
Multiply square feet by depth in feet to get cubic feet, then divide by 27. At 3 inches, 200 sq ft needs 50 cubic feet, or about 1.85 cubic yards before waste.
Convert to bags
If a bag contains 2 cubic feet, divide the required cubic feet by 2 and round up. A cubic yard contains 27 cubic feet, so 2-cu-ft bags require 13.5 bags mathematically; in practice you need 14 full bags per cubic yard.
Account for settling and waste
Add a modest allowance when the bed is uneven or the material will settle. Compare bulk and bag pricing using cubic-foot coverage rather than the sticker price per unit.
Use the calculator
Our Mulch Calculator lets you enter the actual depth and bag size so the output reflects the product you intend to buy.