How this calculator works
Mulch is sold by volume, so the job is to work out the volume of a flat layer: area × depth. We convert the depth from inches to feet, multiply by the area to get cubic feet, then divide by 27 for cubic yards. Standard bags hold 2 or 3 cubic feet.
Worked example: a 20 × 10 ft bed (200 ft²) mulched 3 in deep needs 200 × 0.25 = 50 ft³, which is 1.85 yd³. That is 25 bags of 2 ft³, or 17 bags of 3 ft³.
How far does a cubic yard of mulch go?
One cubic yard covers this much area at each depth.
| Mulch depth | Area covered by 1 yd³ | Bags (2 ft³) per yd³ |
|---|---|---|
| 1 in | 324 ft² | 13.5 |
| 2 in | 162 ft² | 13.5 |
| 3 in | 108 ft² | 13.5 |
| 4 in | 81 ft² | 13.5 |
Mulch needed by bed size (cubic yards)
Bed area in square feet against mulch depth.
| Bed area | 2 in deep | 3 in deep | 4 in deep |
|---|---|---|---|
| 50 ft² | 0.31 yd³ | 0.46 yd³ | 0.62 yd³ |
| 100 ft² | 0.62 yd³ | 0.93 yd³ | 1.23 yd³ |
| 200 ft² | 1.23 yd³ | 1.85 yd³ | 2.47 yd³ |
| 300 ft² | 1.85 yd³ | 2.78 yd³ | 3.70 yd³ |
| 500 ft² | 3.09 yd³ | 4.63 yd³ | 6.17 yd³ |
| 1000 ft² | 6.17 yd³ | 9.26 yd³ | 12.35 yd³ |
Tips before you buy
- 2 to 3 inches is right for most beds. Thicker layers can suffocate roots and stay soggy, while thinner ones let weeds through.
- Keep mulch a few inches back from tree trunks and plant stems. Piling it against bark invites rot and pests (the "mulch volcano").
- Mulch settles and breaks down, so a bed laid at 3 in will be nearer 2 in by next season. Refresh it rather than piling on more.
- For beds over about 2 cubic yards, bulk is usually cheaper than bags. Check the delivery fee.
Quick answers by size
Tools & materials for this project
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Frequently asked questions
How many bags of mulch are in a cubic yard?
A cubic yard is 27 ft³. That is 13.5 bags of 2 ft³ or 9 bags of 3 ft³.
How deep should mulch be?
Two to three inches for most flower beds and around shrubs and trees. Use the lower end for fine mulch and for plants that dislike wet crowns.
How much area does one cubic yard of mulch cover?
About 324 ft² at 1 in deep, 162 ft² at 2 in, and 108 ft² at 3 in.
Is it cheaper to buy mulch in bulk or in bags?
Bulk usually wins for anything over a yard or two, since bagged mulch costs more per cubic foot. For small beds the bags are convenient and the delivery fee on bulk can erase the saving. The cost comparison above helps you decide.
Related calculators & guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.