Mulch Calculator
Measure bed dimensions
Choose desired mulch depth
Adjust waste & bag size
Measure your garden bed length and width in feet. For irregular shapes, divide the area into smaller rectangles.
Select depth in inches. Standard weed suppression and moisture retention requires 2 to 3 inches of wood mulch.
Keep the default 10% waste factor for edge spill, then select standard 2 cu ft or 3 cu ft bag sizes.
Formula
Example calculation
We compute mulch volume using three standard American landscape equations:
Suppose you have a flower bed measuring 10 feet wide by 20 feet long and want a 3-inch layer of bark mulch:
1. Cubic feet = length (ft) × width (ft) × depth (in) ÷ 12 2. Cubic yards = cubic feet ÷ 27 3. Total bags = cubic feet ÷ selected bag size, rounded up to the next whole bag.
Base volume = 10 × 20 × (3 ÷ 12) = 50 cubic feet. Adding a 10% allowance yields 55 cubic feet (2.04 cubic yards). Dividing by 2 cubic feet per bag equals 27.5, which rounds up to 28 bags.
How deep should mulch be
Bag versus bulk mulch
For standard flower beds and garden borders, a 2 to 3-inch layer balances weed prevention with soil aeration. Tree rings and shrub borders benefit from 3 to 4 inches. Avoid piling mulch directly against plant stems or tree trunks.
Bagged mulch (typically 2 or 3 cu ft) offers easy handling for smaller yard projects under 2 cubic yards. Bulk mulch delivered by local landscape suppliers is significantly more economical once your project requires 3 or more cubic yards.
How much does a yard cover?
Why add a waste allowance?
How many bags in a cubic yard?
One cubic yard of mulch covers 108 square feet at 3 inches deep, or 162 square feet at 2 inches deep.
Adding 10% accounts for uneven ground, settling after watering, and spillage along garden bed edges.
There are 13.5 bags of 2 cu ft mulch in one cubic yard, or 9 bags of 3 cu ft mulch.