Mulch Calculator
Bags or cubic yards for any bed — with depth guidance for every mulch type.
Start here: measure your bed, then set the depth for your mulch type — 2–3 in for shredded bark, 3–4 in for wood chips or nuggets. The chart below shows what one bag covers.
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.