Free tool
Mulch calculator
Enter your bed's area and mulch depth to get cubic yards, cubic feet and the number of 2 or 3 cu ft bags, plus a hint on whether bulk delivery makes sense.
You need
0.67 yd³
- Cubic feet
- 18
- Bags of 2 cu ft
- 9
- Bags of 3 cu ft
- 6
Under a cubic yard, bags are simpler: no delivery charge and nothing to shovel off the driveway.
How it works
Mulch is sold by volume. Area in square feet × depth in inches ÷ 12 gives cubic feet; divide by 27 for cubic yards (so cubic yards = area × depth ÷ 324). Bags are usually 2 cu ft, sometimes 1.5 or 3 cu ft: check the label and round up to whole bags.
For an irregular bed, split it into rectangles and add the areas. For a ring around a tree, use 3.14 × radius × radius.
Worked example
A 12 × 6 ft bed (72 sq ft) at 3 inches needs 72 × 3 ÷ 12 = 18 cu ft = 0.67 cubic yards, or 9 bags of 2 cu ft. A 100 sq ft bed at 3 inches needs 0.93 cubic yards, or 13 bags.
Bags of 2 cu ft by bed size
| Bed area | 2 in deep | 3 in deep | 4 in deep |
|---|---|---|---|
| 25 sq ft | 3 bags (0.15 yd³) | 4 bags (0.23 yd³) | 5 bags (0.31 yd³) |
| 50 sq ft | 5 bags (0.31 yd³) | 7 bags (0.46 yd³) | 9 bags (0.62 yd³) |
| 72 sq ft | 6 bags (0.44 yd³) | 9 bags (0.67 yd³) | 12 bags (0.89 yd³) |
| 100 sq ft | 9 bags (0.62 yd³) | 13 bags (0.93 yd³) | 17 bags (1.23 yd³) |
| 200 sq ft | 17 bags (1.23 yd³) | 25 bags (1.85 yd³) | 34 bags (2.47 yd³) |
| 300 sq ft | 25 bags (1.85 yd³) | 38 bags (2.78 yd³) | 50 bags (3.7 yd³) |
| 500 sq ft | 42 bags (3.09 yd³) | 63 bags (4.63 yd³) | 84 bags (6.17 yd³) |
More detail: How much mulch do I need?
Plant lists by condition
Sample beds of 12 × 6 ft with quantities worked out the same way as this tool.
Questions and answers
- How do I calculate mulch in cubic yards?
- Multiply the area in square feet by the depth in inches and divide by 324. A 100 sq ft bed at 3 inches needs 100 × 3 ÷ 324 = 0.93 cubic yards.
- How many bags of mulch are in a cubic yard?
- A cubic yard is 27 cubic feet: 13.5 bags of 2 cu ft or 9 bags of 3 cu ft. Round up to whole bags.
- How deep should mulch be?
- 2 to 3 inches for most beds, no more than about 4. Keep it a few inches back from stems and trunks.