Landscaping
Mulch Calculator
Work out mulch volume from bed area and the depth the planting actually needs.
Result
Bulk delivery is dramatically cheaper than bags above about two cubic yards. One cubic yard covers roughly 108 square feet at 3 inches deep.
Get a Free Business AuditWhat moves the number
- Depth, which is the input people guess at and which drives the whole number.
- Bed area measured properly, since irregular beds are routinely underestimated by eye.
- Whether existing mulch is being topped up or replaced, which changes the depth required.
Where this one goes wrong
Mulching too deep against trunks and stems. Piling mulch against a trunk holds moisture on the bark and invites rot and pests, and the customer blames whoever laid it. Depth is a horticultural decision as well as a quantity one.
Before you quote
- Whether old mulch should be removed or topped, since accumulated layers suffocate roots.
- Bulk delivery access, because a truck that cannot reach the beds changes the labour completely.
- Whether the beds need edging first, which is separate work.
Questions
About this calculator
How deep should mulch be laid?
Enough to suppress weeds and hold moisture without smothering roots. Too thin does not work and too thick causes problems, and the right depth depends on the material and the planting rather than on a single number.
Should old mulch be removed?
If layers have built up over several seasons, yes. Accumulated mulch compacts, sheds water rather than absorbing it, and can starve roots of air.
Bags or bulk?
Bulk is cheaper per unit and needs somewhere to tip it and a way to move it. On a small bed with poor access, bags can genuinely work out better once the barrow time is counted.
The formula
cubic yards = length × width × (depth ÷ 12) ÷ 27
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How to use this calculator
- Length (ft) (ft). Enter your own figure; the page starts at 40 ft.
- Width (ft) (ft). Enter your own figure; the page starts at 8 ft.
- Mulch depth (inches) (in). Enter your own figure; the page starts at 3 in.
- Waste / compaction allowance (%). Enter your own figure; the page starts at 5%.
- Cost per cubic yard delivered ($). Enter your own figure; the page starts at $42.
The result updates as you type, so you can try a figure, see what it does to cubic yards needed, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Length (ft) | 40 ft |
| Width (ft) | 8 ft |
| Mulch depth (inches) | 3 in |
| Waste / compaction allowance | 5% |
| Cost per cubic yard delivered | $42 |
What comes out
| Result | Value |
|---|---|
| Cubic yards needed main result | 3.1 |
| Cubic feet | 84.0 |
| Approximate tons | 1.6 |
| Estimated cost | $130.67 |
| 2 cu ft bags | 42 |
That bed needs 3.1 cubic yards of mulch at 3" deep, about 42 bags, or $130.67 delivered in bulk.
How sensitive the answer is
Holding everything else steady and changing only cost per cubic yard delivered, this is what happens to cubic yards needed. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Cost per cubic yard delivered ($) | Cubic yards needed |
|---|---|
| $21 | 3.1 |
| $32 | 3.1 |
| $42 example above | 3.1 |
| $63 | 3.1 |
| $84 | 3.1 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Length (ft) (ft)
- Measured in ft, starting at 40 ft.
- Width (ft) (ft)
- Measured in ft, starting at 8 ft.
- Mulch depth (inches) (in)
- Measured in in, starting at 3 in.
- Waste / compaction allowance (%)
- A percentage, between 0 and 60, starting at 5%.
- Cost per cubic yard delivered ($)
- A money amount, starting at $42.
What the results tell you
| Result | What it is |
|---|---|
| Cubic yards needed | The headline result. A decimal figure. |
| Cubic feet | A decimal figure. |
| Approximate tons | A decimal figure. |
| Estimated cost | A money figure. |
| 2 cu ft bags | A number. |
Seasonality is not in this
Coverage and material figures assume the area you enter. Slope, access for machinery, existing growth and the time of year all affect both quantity and labour, and none of them appear in a calculation like this.
Keep going
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