Enter your bed size and depth to find out exactly how much mulch you need — in cubic yards, bags, and total cost.
Mulch is measured by volume, so the formula is area × depth. Measure your bed's length and width, choose a depth, and this calculator converts it into the units stores use — cubic yards and 2 cubic foot bags — plus an estimated cost so you buy the right amount in one trip.
For most garden beds, 2–3 inches is ideal — enough to suppress weeds and hold moisture without smothering roots. Use 3–4 inches for heavy weed control or bare soil, and keep it to about 1–2 inches around trees, never piled against the trunk. Deeper isn't better; too much mulch blocks water and air from reaching roots.
Bagged mulch comes in 2 cubic foot bags, and it takes 13.5 bags to equal one cubic yard. Bags are easy for small beds, but bulk delivery is usually far cheaper once you need more than about 10–15 bags. This calculator shows both so you can compare.
| Depth | Area covered by 1 yd³ | Bags per yd³ |
|---|---|---|
| 1 inch | ~324 sq ft | 13.5 |
| 2 inches | ~162 sq ft | 13.5 |
| 3 inches | ~108 sq ft | 13.5 |
| 4 inches | ~81 sq ft | 13.5 |
Pull weeds before mulching, and water the bed first if the soil is dry. Refresh the top layer once a year rather than piling on more — fluff the existing mulch to revive its look. Organic mulches (bark, wood chips) break down and feed the soil; rubber and stone don't decompose but need occasional topping up where they thin out.