How Much Mulch for 400 Square Feet?
400 sq ft (about 20 × 20 ft) covered 3 inches deep takes about 4.07 cubic yards of mulch, or 55 bags of 2 cu ft. That includes 10% extra for settling and uneven ground.
Mulch for 400 sq ft by depth
| Depth | Cubic yards | Cubic feet | 2 cu ft bags | Weight |
|---|---|---|---|---|
| 2 in (refresh) | 2.72 | 73.3 | 37 | 1,900 lb |
| 3 in (new bed) | 4.07 | 110 | 55 | 2,850 lb |
| 4 in (weed control) | 5.43 | 146.7 | 74 | 3,800 lb |
Volume = area × depth ÷ 12 = 400 × 3 ÷ 12 = 100 cu ft before the 10% extra. One cubic yard covers about 108 sq ft at 3 inches (162 at 2 in, 108 at 3 in, 81 at 4 in).
Gravel for 400 sq ft
| Depth | Cubic yards | Tons |
|---|---|---|
| 2 in (light path) | 2.72 | 3.8 |
| 3 in (path, patio base) | 4.07 | 5.7 |
| 4 in (driveway base) | 5.43 | 7.6 |
Gravel is sold by the ton or the yard. These tons assume about 2,800 lb per cubic yard, which varies with stone type and moisture. Sand and topsoil are in the mulch and gravel calculator.
Tips before you order
Spread 2 to 3 inches around established plants and keep mulch a few inches away from trunks and stems. If your bed is not a rectangle, find its area first with the square footage calculator. Bulk delivery is usually cheaper than bags once you need a yard or two; bags make sense for small beds. For a hard surface under gravel, see how much concrete you need for a slab.
Frequently asked questions
How much mulch do I need for 400 square feet?
At the usual depth of 3 inches you need about 4.07 cubic yards of mulch, or 55 bags of 2 cubic feet, including 10% extra for settling and uneven ground. At 2 inches it is 2.72 yards (37 bags) and at 4 inches 5.43 yards (74 bags).
How many bags of mulch cover 400 square feet?
55 bags of 2 cu ft cover 400 sq ft at 3 inches deep. A 2 cu ft bag covers about 8 square feet at 3 inches, so the count is the area divided by 8, plus the extra.
How much does 4.07 yards of mulch weigh?
Mulch weighs roughly 700 pounds per cubic yard, so 4.07 yards is about 2,850 pounds (1.43 tons). Wet mulch can weigh considerably more, so check what your truck or trailer can carry.
How much gravel do I need for 400 square feet?
For 3 inches of gravel over 400 sq ft you need about 4.07 cubic yards, which is roughly 5.7 tons at about 2,800 pounds per yard. Gravel types vary in weight, so confirm the tonnage with your supplier.
Other areas
Planning figures for a flat bed. Bag sizes and material weights differ by brand and supplier, so confirm with yours.