Construction & Home · Area & Materials
Formula verified
Mulch Calculator
Enter your garden bed's area, the depth of mulch you want, and a waste allowance to see how much to buy — in cubic yards for bulk delivery, or whole bags.
Bed
sq ft
in
%
cu ft
$
On-screen number pad
Tap to type into the highlighted field
Cubic yards needed
2.04
28 bags
Cubic feet
55
Bags to buy
28
Step-by-step proofCheck by hand
This is a material-quantity estimate. Actual coverage varies by mulch type (shredded bark settles differently than nuggets or straw) and how evenly it's spread. Round up rather than down, and check the bag size against what's actually sold locally.
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How the mulch quantity is calculated
Bed area times desired depth (converted from inches to feet) gives the raw volume needed in cubic feet, increased by the waste allowance for uneven ground and spillage. That's converted to cubic yards for a bulk delivery order, and divided by the bag size — rounded up, since a partial bag still has to be bought — for a bagged-mulch shopping list.
The formula
cu ft = area × (depth ÷ 12) × (1 + waste%) · cu yd = cu ft ÷ 27 · bags = ⌈cu ft ÷ bag size⌉
Worked example
A 200 sq ft bed at 3 inches deep with 10% waste: 200 × 0.25 × 1.10 = 55 cu ft, which is 2.04 cubic yards — 28 bags at 2 cu ft per bag.
Frequently asked questions
How deep should mulch be?
2 to 4 inches is the commonly recommended range for most garden beds — enough to suppress weeds and retain moisture without smothering plant roots or trunks. Deeper isn't always better; piling mulch against a trunk or stem (a "mulch volcano") can cause rot.
Why does the calculator use cubic yards for bulk mulch?
Bulk (unbagged) mulch delivered by a landscaping supplier is almost always sold and priced by the cubic yard, not by area or weight. Bagged mulch, by contrast, is sold by a fixed volume per bag (commonly 2 cubic feet), which is why the calculator also shows a bag count.
Why round the bag count up?
Because a bag is sold whole — needing 13.2 bags in practice means buying 14, the same "round up, it's sold whole" rule this site's Concrete and Tile calculators use for bags and boxes.
Sources and method
- Standard published landscaping-estimation practice — area-based mulch volume with a waste allowance.