It's the question we get asked more than any other: "How much should I order?" Since everything we supply is sold and delivered per cubic metre, getting this right saves you from a wasted second delivery — or a driveway full of leftover material. Here's a simple way to work it out yourself.
The Basic Formula
For any garden bed, path or area, the calculation comes down to three measurements:
Length (m) × Width (m) × Depth (m) = Volume in cubic metres (m³)
The tricky part is usually the depth, since it's easy to underestimate. Here's a general guide depending on what you're laying:
| Material | Recommended depth |
|---|---|
| Garden soil (beds, veggie patches) | 150–300mm (0.15–0.3m) |
| Mulch (garden beds, borders) | 50–75mm (0.05–0.075m) |
| Decorative pebbles (pathways, borders) | 30–50mm (0.03–0.05m) |
| Sand (paving joints, base layers) | Varies by application — check with us if unsure |
A Worked Example
Say you're mulching a garden bed that's 4m long and 2m wide, at a depth of 75mm (0.075m):
4m × 2m × 0.075m = 0.6m³ of mulch
Or if you're filling a raised veggie bed that's 2m long, 1m wide and 0.3m deep:
2m × 1m × 0.3m = 0.6m³ of soil
Small numbers add up quickly once you're working across multiple beds, so it's worth measuring each area separately and adding the totals together.
A Few Things That Trip People Up
- Irregular shapes — break the area into rough rectangles or triangles and calculate each separately, then add them up.
- Settling — soil and mulch settle over time, particularly after the first watering or rain. Ordering slightly more than your exact calculation (an extra 10% or so) is a reasonable buffer for larger jobs.
- Existing ground level — if you're topping up an existing bed rather than starting from scratch, measure the actual gap you're filling, not the full bed depth.
Still Not Sure?
If the maths feels fiddly or your project has multiple areas with different materials, just get in touch through our Contact page with your measurements — we're happy to work out the quantities with you before you order. It's better to get it right the first time than to end up with a half-used pile of soil in the driveway.
Browse our full range of soils, sand, mulch and decorative materials in the Catalog.
