Free landscaping calculator
Mulch Calculator — cubic yards & bags
Enter your bed size and mulch depth to instantly see how many cubic yards or bags to buy.
Rounded up to the nearest quarter yard so you don't run short.
How much mulch do I need?
Mulch is sold by volume: bulk suppliers sell it by the cubic yard, and garden centers sell 2 cubic foot bags. To find how much you need, multiply your bed's length by its width to get square feet, multiply by your depth in feet, then divide by 27 to convert cubic feet to cubic yards. The calculator above does this instantly and rounds up, since running out of mulch mid-project means a second trip.
| Depth | 1 cubic yard covers |
|---|---|
| 1 inch | 324 sq ft |
| 2 inches | 162 sq ft |
| 3 inches | 108 sq ft |
| 4 inches | 81 sq ft |
How deep should mulch be?
For a new bed, 3 inches is the sweet spot: deep enough to suppress most weeds and hold soil moisture, shallow enough that water and air still reach plant roots. Refreshing an existing bed usually takes just 1–2 inches. Keep mulch a few inches away from tree trunks and plant stems — piling it against bark traps moisture and invites rot.
Bags or bulk delivery?
One cubic yard equals 13.5 standard 2 cu ft bags. Above roughly one cubic yard, bulk delivery from a landscape supplier is usually cheaper per yard and saves hauling a dozen-plus bags in your car. Under a yard, bags are simpler and let you spread the work across a weekend.
Frequently asked questions
How much does a yard of mulch cover?
One cubic yard of mulch covers 324 square feet at 1 inch deep, 162 square feet at 2 inches, or about 108 square feet at the recommended 3-inch depth.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 standard 2 cubic foot bags, or 9 of the larger 3 cubic foot bags.
How often should mulch be replaced?
Organic mulch breaks down over time. Most beds need a 1 to 2 inch top-up once a year, typically in spring. A full replacement is only needed if the old layer has fully decomposed or become compacted.
Should I remove old mulch before adding new?
Usually not. Rake the old layer to break up any crust, then top up to your target depth. Only remove old mulch if the combined depth would exceed about 4 inches, or if the old material shows mold or pest problems.