Mulch calculator
Enter bed area and mulch depth, pick a bag size, and read cubic yards plus bag counts. Depth is the variable, not an invented waste factor, with Extension guidance on the page. The table lists two through four inch depths with sourced conversion and rounded purchase counts. Share links keep inputs after the hash only.
Bed and depth
Depth series
Waiting for bed dimensions.
Bag conversion follows CalculatorSoup: one cubic yard equals twenty-seven cubic feet, or thirteen point five two-cubic-foot bags. Purchase counts round up and show leftover explicitly.
- Cubic yards
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- Conversion
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- Purchase
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- Requests
- · from Resource Timing
- Script
- · KB of a 100 KB budget
No mulch waste factor
Mulch settles. This page treats depth as the variable instead of inventing an overage percentage. That matches University of Illinois Extension guidance for composted versus coarse mulch depths.
Two numbers, not one
The sourced conversion and the purchasable bag count differ when rounding up. One cubic yard at two cubic foot bags is thirteen point five bags in the arithmetic and fourteen bags at the store.
Topping up is a different sum
This page answers how much mulch a bare bed needs. Most beds are not bare. Mulch already down counts toward the depth you are aiming for, so if two inches remain from last year and you want three, you are buying one inch, not three. Push a finger to the soil in three or four spots and measure what's actually there before you enter a depth. Beds settle unevenly, and the thin end is usually the shady end.
Bags or bulk, and where the line falls
The bag count above is the number to carry; the yard figure is the number to buy in bulk, and the two are priced on different terms. Delivery is usually a flat charge, so a small bulk order pays it on very little material while a large one barely notices it. Price both ways at your own volume rather than assuming one wins. And bulk mulch is often sold by the scoop rather than the cubic yard, and a scoop is not a standard unit: ask the supplier what fraction of a yard theirs is before you compare their price to anything on this page.
Questions
Where does thirteen point five come from?
CalculatorSoup publishes that one cubic yard is twenty-seven cubic feet, which is thirteen point five two-cubic-foot bags. The purchase row rounds up to fourteen.
What depth should I use?
University of Illinois Extension recommends two to four inches overall, with composted mulch at two to three inches and coarse mulch at three to four inches.
Should the depth go right up to the trunk?
No, and this is the one place where following a depth figure does damage. Depth guidance describes the open bed surface. Mulch piled against a trunk or a stem holds moisture against bark that is not built for it and invites rot and rodents. Keep the base of the plant clear and taper the depth in toward it. The calculator has no way to know what is planted in the bed, so it computes the bed, and you place it.
Related tools
More material tools live on the home project tools hub, including the concrete calculator and the flooring calculator.