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Volume Calculator
Work out exactly how much mulch, soil, sand, gravel or crushed rock your project needs. Pick the shape of each garden bed or area, enter its size and depth, and add as many areas as you like — we’ll total the cubic metres for you.
How the calculation works
Volume is simply the area of your space multiplied by how deep you want the material laid.
Rectanglelength × width × depth
Squareside × side × depth
Triangle½ × base × height × depth
Circleπ × radius² × depth
Semicircle½ × π × radius² × depth
Typical depths
- Mulch — 50–75 mm for garden beds, up to 100 mm to suppress weeds.
- Garden soil — 100–300 mm depending on what you’re planting.
- Crushed rock / road base — 75–100 mm for paths, 100–150 mm under a driveway.
- Bedding sand — 25–30 mm under pavers.
Odd-shaped area? Break it into a few simple shapes, add one area for each, and the calculator will add them together. Allow a little extra for settling and uneven ground.