Work out how much topsoil you need for a new lawn, flower bed or raised bed, including extra for the soil settling.
Area × the depth you want once the soil has settled.
Loose topsoil settles by roughly 10–20% once firmed and watered, so we add your settlement allowance (15% by default).
We use 1,400 kg/m³ and round up to whole bulk bags of about 850 kg. Topsoil weight varies with moisture, so treat it as a guide.
These are estimates for ordering materials, not a structural design. Check site conditions, and anything unusual, with a qualified builder or engineer.
100–150mm of good topsoil is ideal for turf or seed. Less than about 75mm and the lawn will dry out quickly in summer.
Enter the bed's length, width and depth. For vegetables a depth of 300–450mm is typical. Many people mix in compost at about one part to three.
Roughly 4 m² at 150mm deep. Some suppliers sell topsoil bags by volume (0.7–1 m³) rather than weight, so check the bag size.
Topsoil that's been sieved to remove stones, roots and clods. It's easier to level and better for lawns.