Mulch Calculator

Measuring your mulch is simple. First, measure the length and width of your garden bed in feet. Next, decide how deep you want the mulch — most beds use 3 inches, which is the default here. Enter those three numbers and the calculator instantly shows how many cubic yards of bulk mulch and how many bags you need to buy. Working in meters, or buying 3 cu ft bags instead of the standard 2 cu ft bags? Open More options to switch units, change the bag size, or add a price to estimate your total cost.

Mulch is sold two ways: loose in cubic yards (bulk, delivered or scooped at a garden center) and in bags, almost always 2 cubic feet each. Because there are 27 cubic feet in a cubic yard, one cubic yard equals about 13.5 standard bags. The amount you need depends on three things — the area of your bed and how deep you spread the mulch. A common question is *how much mulch for a 10x20 bed*: at 3 inches deep that is 200 sq ft × 0.25 ft = 50 cubic feet, or about 1.85 cubic yards (25 bags). Bulk is usually cheaper per cubic foot once you need more than about 6–8 bags, so this tool shows both so you can compare.

Cubic feet = length (ft) × width (ft) × depth (ft), where depth in feet = depth in inches ÷ 12.

Then:
- Cubic yards = cubic feet ÷ 27
- Bags = cubic feet ÷ bag size (2 or 3 cu ft), rounded up

Example: a 10 ft × 20 ft bed at 3 in deep = 200 × (3 ÷ 12) = 50 cubic feet = 50 ÷ 27 = 1.85 cubic yards = 50 ÷ 2 = 25 bags.

Example 1 — small border, by the bag. A 4 ft × 8 ft border at 2 inches deep: 32 sq ft × (2 ÷ 12) = 5.33 cubic feet. That is 0.20 cubic yards, or 3 bags of 2 cu ft mulch — an easy job to do without bulk delivery.

Example 2 — large bed, buy in bulk. A 20 ft × 30 ft bed at 3 inches deep: 600 sq ft × 0.25 = 150 cubic feet = 5.56 cubic yards. That is 75 standard bags, so bulk delivery is the smart, cheaper choice here.

Example 3 — refreshing existing mulch. For a yearly top-up you usually only add 1 inch. A 10 ft × 20 ft bed at 1 inch deep is just 16.7 cubic feet, about 9 bags — a third of a full 3-inch install.

- 3 inches is the sweet spot. It blocks weeds and holds moisture without smothering roots. Go 2 inches for a light refresh, and never pile mulch against tree trunks.
- Round bulk up. Suppliers sell bulk in half- or full-yard scoops, so order the next round number above your result.
- Bulk beats bags past ~8 bags. If you need more than about 6–8 bags, price out a bulk cubic yard — it is usually cheaper and less lifting.
- Buy ~5% extra for uneven ground and settling.
- Bag math shortcut: one cubic yard ≈ 13.5 bags of 2 cu ft, or 9 bags of 3 cu ft.