Mulch calculator
Add each bed, the depth you want and any mulch already down. You get cubic yards for bulk delivery and the number of bags in the size you buy.
Inputs
Result
Mulch coverage chart
Square feet covered by one cubic yard and one bag at each depth.
| Depth | Sq ft per cubic yard | Sq ft per 2 cu ft bag |
|---|
How it is worked out
One cubic yard spread 3 in deep covers 108 sq ft, and one 2 cu ft bag covers 8 sq ft. That makes a yard worth 13.5 bags, which is why bulk delivery wins quickly on any bed bigger than a few hundred square feet.
How deep to mulch
Most extension services recommend 2 to 4 in. Thinner lets weeds through; thicker can starve roots of air and keep bark wet. Keep mulch a few inches back from tree trunks and plant stems, and never pile it against the trunk.
Wood mulch breaks down and settles over a season, so a bed laid at 3 in may be 1 to 2 in a year later. Measure what is there and top up to the depth you want instead of adding a full layer every spring.
Questions
How much area does a yard of mulch cover?
324 sq ft at 1 in deep, 162 at 2 in, 108 at 3 in and 81 at 4 in.
How many bags of mulch are in a yard?
13.5 bags of 2 cu ft, 9 bags of 3 cu ft, or 27 bags of 1 cu ft. A cubic yard is 27 cubic feet.
How many bags of mulch do I need for 100 square feet?
At 3 in deep, 25 cu ft, which is 13 bags of 2 cu ft. At 2 in deep, 17 cu ft, or 9 bags.
How deep should mulch be?
2 to 4 in for most beds. Use the shallower end around shallow-rooted plants and on heavy clay soil, and keep it pulled back from trunks.
Should I remove old mulch before adding new?
Not usually. Measure what is left and top it up to the depth you want; the calculator subtracts what is already there. Rake it loose first if it has matted.
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