Landscape Material Volume Calculator
Estimate cubic metres and tonnes of gravel, mulch or soil from area, placed depth, settlement allowance and supplier bulk density.
Your results
Calculation breakdown
- Loose volume
- area m² × depth m × (1 + settlement %)
Worked example
Covering 45 m² to 75 mm gives 3.375 m³ finished; with 15% settlement allow 3.881 m³, about 5.82 t at 1.5 t/m³.
Assumptions
- Depth is uniform over the measured area.
- Bulk density and settlement allowance come from the selected material supplier.
Sources
Rates effective 23 August 2026.
How this calculator works
Landscape materials are typically ordered by loose volume or mass, while the design depth is measured after spreading or compaction. The calculator converts millimetres to metres, adds a user-selected settlement allowance to net geometric volume and uses supplier bulk density for an indicative tonnage.
Frequently asked questions
Why does bulk density matter?
The same cubic metre can have very different mass depending on material, particle grading, moisture and how loosely it is loaded.
What settlement allowance should I use?
Ask the supplier or installer for a value suited to material type, moisture, compaction method and the required finished depth.
Should irregular areas be measured separately?
Yes. Split the site into measurable shapes, total their areas and use different calculations where layer depths or materials change.