Topsoil calculator
Cubic yards, cubic metres and bags of topsoil
Type the area and depth. The example is a 10 ft by 20 ft area, 4 inches deep, in 0.75 cu ft bags.
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- Same volume, other units
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- Bags
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- Before the extra
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An estimate of quantity from the sizes you typed, not an order list or a price. Check structural work, and anything covered by a building code, with your local code or a qualified person.
How the amount is worked out
Volume is area x depth, with the depth turned into feet or metres first: 4 inches is 0.333 ft and 100 mm is 0.1 m. Loose soil settles after it is spread, firmed and watered, so the extra allowance is added on top. The answer is shown in cubic yards (US bulk), cubic metres (bulk elsewhere) and bags.
Raised beds
For a raised bed, the length and width are the inside of the bed and the depth is how deep you will fill it. A 1.2 m x 2.4 m bed filled 300 mm deep holds 0.864 m³ before any allowance.
Worked example
10 ft x 20 ft x 4 in: 10 x 20 x 0.333 = 66.7 cu ft, which is 2.47 cu yd. Add 10%: 73.3 cu ft (2.72 cu yd). In 0.75 cu ft bags that is 97.8, so 98 bags. That many bags is why most people buy bulk for anything bigger than a bed or two.
Bags and bulk
Bags are sold by volume, printed on the bag. Choose Other to type a different size. Bulk soil is sold by the cubic yard or cubic metre, sometimes by weight; soil weighs more when wet, so ask the supplier how they measure.
What it leaves to you
It does not say how deep soil must be for a lawn or for particular plants, or whether you need to change the levels near a building. Ask your supplier, a garden adviser or a qualified person.
Defaults and where they come from
Every default is only a starting point. Change any box to match what you are buying or building.
| Default | Value | Source |
|---|---|---|
| US bag sizes | 0.75 cu ft (also 1 and 1.5 cu ft) | Sizes printed on US bagged topsoil. Choose Other for any other size. |
| UK and Australian bag sizes | 25 litres (also 40 and 50 litres) | Sizes printed on UK and Australian bagged soil. Choose Other for any other size. |
| Settling allowance | 10% (usual 10 to 20%) | Common practice, because loose soil settles once spread and watered. No standard sets a figure. |
| Conversions | 1 cu yd = 27 cu ft; 1 m³ = 1,000 litres | Exact definitions. |