Mulch Calculator
Bags or cubic yards for any bed — with depth guidance for every mulch type.
Quick answer
Multiply your bed's area (sq ft) by the depth in inches, then divide by 324 — that's the cubic yards of mulch needed. One cubic yard equals 13.5 standard 2-cubic-foot bags and covers about 108 sq ft at 3 inches deep. Enter your measurements above for exact bags.
Reference chart
| Depth | One 2 cu ft bag covers | Bags per 100 sq ft |
|---|---|---|
| 1 inch | 24 sq ft | 4.2 bags |
| 2 inches | 12 sq ft | 8.4 bags |
| 3 inches | 8 sq ft | 12.5 bags |
| 4 inches | 6 sq ft | 16.7 bags |
Good to know
How deep should mulch be?
It depends on the material: fine mulches (shredded bark, compost) work best at 1–2 inches; medium shredded mulch at 2–3 inches; coarse wood chips and bark nuggets at 3–4 inches. Deeper is not better — piling mulch too thick suffocates roots and invites pests.
Keep mulch away from trunks
Leave a clear gap of a few inches around plant stems and about 6 inches around tree trunks. The infamous "mulch volcano" piled against a trunk traps moisture against the bark and causes rot.
Bags or bulk?
One cubic yard equals 13.5 standard bags. As a rule of thumb, below about 1 cubic yard, bags are easier; above 2 cubic yards, a bulk delivery is usually cheaper per unit and saves a dozen trips — compare your local prices with the cost fields above. Shredded bark settles over time, so many landscapers add roughly 10% extra.