How to Calculate How Much Landscape Material You Need
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One of the most common questions we get at Burrum Landscape Supplies is: "How much do I need?" Whether you're laying a fresh bed of mulch, topping up the garden with soil, or gravelling a driveway, getting the quantity right saves money and avoids a second trip.
The good news? It's straightforward once you know the formula.
The Basic Formula
For most landscaping materials, the calculation is:
Volume (m³) = Length (m) × Width (m) × Depth (m)
That gives you cubic metres. Most bulk materials are sold and delivered by the cubic metre or tonne.
What Depth Should I Use?
Depth depends on what you're doing:
- Garden mulch: 75–100mm for a fresh layer; 50mm for a top-up
- Garden soil or fill: 150–200mm for new garden beds
- Decorative gravel or aggregate: 50–75mm
- Driveway or path gravel: 75–100mm compacted
- Crusher dust or road base: 100mm for pathways; 150mm for driveways
A Worked Example
Say you want to mulch a garden bed that's 8 metres long, 3 metres wide, and you want a 75mm deep layer:
8 × 3 × 0.075 = 1.8 cubic metres
We'd recommend rounding up to 2m³ to account for uneven ground and settling.
Use Our Free Volume Calculator
Don't want to do the maths yourself? We've got a free volume calculator on our website — just plug in your measurements and it works it out for you. It covers mulch, soil, gravel, sand, and more.
Not Sure Which Product?
If you're not sure which material suits your project, give us a call on 0408 466 287 — we're happy to talk it through. You can also pop into the yard at 50 Old Bruce Highway, Howard and view our sample display of everything. We supply and deliver across Howard, Hervey Bay, Maryborough, Burrum Heads, and the wider Wide Bay and Fraser Coast region.