Answer: Enter your values and the Mulch Calculator returns the exact result instantly — formula, worked example, and a plain-English explanation are included below the tool.
Cubic yards & bags of mulch from area and depth
Enter your bed's length and width in feet (or type a known square footage, which overrides the dimensions), choose a depth from 1 to 4 inches, and set your local prices. The calculator returns cubic yards, the rounded half-yard order quantity, the number of 2-cubic-foot bags, coverage area, and both bulk and bagged cost estimates.
The volume math: cubic feet = area × depth ÷ 12, and cubic yards = cubic feet ÷ 27, since one cubic yard is 27 cubic feet. Bags are sized at 2 cubic feet each (the standard big-box mulch bag), so bags = cubic feet ÷ 2, rounded up. Bulk orders are rounded to the next half yard because most landscape suppliers sell in half-yard increments.
The depth dropdown mirrors common practice: 1 inch for a light top-dressing to refresh color, 2 inches for a thin refresh over existing mulch, 3 inches as the standard depth for a new bed, and 4 inches for new beds where weed suppression is the priority. Going beyond 4–5 inches can suffocate plant roots and is generally not recommended.
Because volume scales linearly with depth, doubling depth doubles the material: the same 200 sq ft bed needs about 0.62 yd³ at 1 inch but 2.47 yd³ at 4 inches.
With the defaults — 20 × 10 = 200 sq ft at 3 inches — volume is 200 × 0.25 = 50 cubic feet = 1.85 cubic yards. The order rounds up to 2.0 yd³, bags come to ceil(50 ÷ 2) = 25, and at $40 per yard bulk costs $80 while 25 bags at $4.50 cost $112.50.
The table compares depths for this same 200 sq ft bed so you can see how quickly material scales. Bulk is almost always the cheaper route past a few yards — the bagged equivalent of one yard is 13.5 bags.
| Depth | Volume (200 sq ft) | Yards | 2 ft³ Bags | Cost @ $40/yd |
|---|---|---|---|---|
| 1 in — topdress | 16.7 ft³ | 0.62 | 9 | $25 |
| 2 in — thin | 33.3 ft³ | 1.23 | 17 | $50 |
| 3 in — standard | 50 ft³ | 1.85 | 25 | $80 |
| 4 in — new bed | 66.7 ft³ | 2.47 | 34 | $100 |
Bulk mulch is sold by the cubic yard (scoop) and typically delivered or shoveled into a trailer; bagged mulch is 2 or 3 cubic feet per bag. At typical prices the math in this calculator usually shows bulk at roughly half the per-yard cost of bags once quantity is meaningful.
For ordering, round up: the calculator already rounds to the next half yard for bulk. A slightly heavy order beats running short, and leftover mulch can be stockpiled for the next top-dressing.
Mulch types differ in coverage behavior and longevity. Shredded hardwood bark knits together on slopes and lasts one to two seasons; pine bark nuggets last longer but float and scatter in heavy rain; dyed mulches hold color longer; stone and rubber never decompose but transfer heat to soil and don't feed it. Organic mulches break down over time, which improves soil but means an annual 1–2 inch refresh — the topdress depth in this calculator's dropdown.
Coverage tips that save material: pull mulch back 3–6 inches from plant crowns, tree trunks, and stems to prevent rot and rodent damage; edge the bed first so the mulch line stays crisp; and water immediately after spreading to settle it. If you're mulching primarily for weed control, lay newspaper or cardboard under a thinner mulch layer rather than stacking mulch dangerously deep.
One cubic yard of mulch dumped covers 324 sq ft at 1 inch, 162 at 2 inches, and 108 at 3 inches — the same coverage math this calculator applies. Suppliers' scoop sizes vary slightly, so if your quote is in scoops, ask how many cubic yards each scoop represents and enter that number here to check the price.
How many cubic feet are in a yard of mulch?
One cubic yard is 27 cubic feet. That equals 13.5 standard 2-cubic-foot bags — which is why bulk mulch is far cheaper per yard than bagged.
How deep should mulch be?
3 inches is the standard for a new bed; 1–2 inches is enough to refresh an existing layer. Avoid piling past 4–5 inches, which can block air and water from reaching roots.
How many bags of mulch equal a yard?
Thirteen and a half 2-cubic-foot bags, or nine 3-cubic-foot bags. The calculator assumes 2 ft³ bags, the most common retail size.
Why does the order round to half yards?
Most bulk suppliers sell in half-yard increments, so the calculator rounds your exact yardage up to the next 0.5 yd³ to give a realistic order quantity.
How do I mulch around trees?
Keep mulch 3–6 inches back from the trunk and spread 2–4 inches out to the drip line. Volcano piles against bark invite rot and pests.