How to calculate mulch or soil
Multiply the area (length × width in feet) by the depth in feet, then divide by 27 to get cubic yards. A 20 × 10 ft bed at 3 inches deep: 200 × 0.25 = 50 cu ft = 1.85 cubic yards. One cubic yard covers about 324 sq ft at 1 inch, 108 sq ft at 3 inches, or 81 sq ft at 4 inches.
Recommended depths
| Use | Depth |
|---|---|
| Mulch around plants and trees | 2–4 in (5–10 cm) |
| Topsoil for a new lawn | 4–6 in (10–15 cm) |
| Raised vegetable beds | 8–12 in (20–30 cm) |
| Gravel paths | 2–3 in (5–8 cm) over a base |
| Gravel driveway | 4–6 in total, in layers |
| Sand under pavers | 1 in (2.5 cm) |
Keep mulch a few inches away from tree trunks and house siding — “volcano” mulching invites rot and pests.
Bags or bulk?
Bagged mulch is usually sold in 2 cu ft bags (13.5 bags per cubic yard) or 3 cu ft bags (9 per yard); in the UK and Australia, 40–60 litre bags are common. For anything over about 2 cubic yards, bulk delivery from a landscape supplier is usually far cheaper per yard.
Weight
Weights vary with moisture, but roughly: mulch 400–800 lb per cubic yard, compost about 1,000–1,200 lb, topsoil about 1 ton, gravel and sand about 1.3–1.4 tons. Check your vehicle’s payload before hauling it yourself. For concrete pads, use the concrete calculator.
Frequently asked questions
How much area does a yard of mulch cover?
About 108 square feet at 3 inches deep, or 162 square feet at 2 inches.
How many bags of mulch are in a yard?
13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet.
How deep should mulch be?
2–4 inches for most garden beds.
How much does a yard of gravel weigh?
About 1.3 to 1.5 tons, depending on the stone and moisture.