Mulch Calculator

Enter the size of your bed and how deep you want the mulch. You'll see bulk cubic yards and the number of bags.

2" to 3" for most beds, 3" to 4" around trees.

How the calculation works

Mulch is sold by volume. Multiply the area in square feet by the depth in feet to get cubic feet:

cubic feet = length × width × (depth in inches ÷ 12)

There are 27 cubic feet in a cubic yard, which is how bulk mulch is sold. Bagged mulch usually comes in 2 or 3 cubic foot bags, so one cubic yard equals 13.5 two-foot bags or 9 three-foot bags.

Worked example

A bed 20 feet long and 4 feet wide, mulched 3 inches deep, is 80 square feet × 0.25 feet = 20 cubic feet. That's 0.74 cubic yards, or 10 bags of 2 cu ft mulch.

Bags or bulk?

Bags are easier for small jobs and don't need a truck. Above about 2 cubic yards (27 two-foot bags), bulk delivery from a landscape supplier usually costs less, even after the delivery fee. Ask whether the supplier sells half-yard increments.

Frequently asked questions

How much area does a cubic yard of mulch cover?

One cubic yard covers 324 square feet at 1" deep, 162 square feet at 2", 108 square feet at 3", and 81 square feet at 4".

How deep should mulch be?

Two to three inches holds moisture and blocks most weeds. Deeper than four inches can keep soil too wet and starve roots of air. Keep mulch a few inches away from tree trunks and plant stems.