Garden Soil & Topsoil Calculator
Work out how much topsoil, compost or soil you need to fill a bed or border.
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soil volume needed
| Volume | – |
|---|---|
| Approx. weight | – |
| 50-litre bags | – |
| Bulk bags (~730 kg) | – |
Garden soil and topsoil calculator
This calculator works out how much topsoil, compost, or garden soil you need to fill a raised bed, border, or planting area. Enter the length, width, and depth, and it returns the volume in cubic metres and litres, the approximate weight, and how many 50-litre bags or bulk bags to buy.
How much soil do I need?
The volume is length × width × depth. Topsoil weighs roughly 1.3 tonnes per cubic metre, though this varies with moisture and how much organic matter it contains. For new beds, a depth of 20–30 cm suits most vegetables and flowers; for laying or topping up a lawn, 2.5–5 cm is usually enough.
Bags vs bulk
Small jobs are easiest with 50-litre bags, but for anything over about 1 m³ a delivered bulk bag is far better value. To plan what to grow in the bed, use our plant spacing calculator, and to feed it, the fertiliser calculator.
Frequently asked questions
How many litres of soil in a cubic metre?
There are 1,000 litres in one cubic metre, so a 1 m³ order equals twenty 50-litre bags.
Disclaimer: Estimates only. Soil density varies — confirm quantities with your supplier.
Recommended soil depths by project
The depth you enter has the biggest effect on the result, so match it to the job. These are typical working depths used by UK and US gardeners. Heavy clay or very stony ground may need the deeper end of each range.
| Project | Depth (cm) | Depth (inches) |
|---|---|---|
| Top dressing an existing lawn | 0.5–1 | ¼–½ |
| New lawn from seed or turf | 10–15 | 4–6 |
| Mulch over beds | 5–7.5 | 2–3 |
| Flower and shrub borders | 20–30 | 8–12 |
| Vegetable beds | 30–45 | 12–18 |
| Raised beds | Full bed height | Full bed height |
Worked example: a new border
A border measuring 5 m long and 1.2 m wide, filled to 30 cm, needs 5 × 1.2 × 0.30 = 1.8 m³ of soil, which is 1,800 litres. Freshly delivered topsoil is loose and settles by around 10–20% once it is firmed and watered, so order 2.0–2.2 m³. That is roughly two bulk bags, or 36–44 bags of 50 litres.
Worked example: levelling for a new lawn
A lawn area of 8 m × 6 m with a 10 cm layer of topsoil needs 8 × 6 × 0.10 = 4.8 m³. At around 1.3 tonnes per m³ for dry screened topsoil, that is roughly 6.2 tonnes — enough that bulk delivery is far cheaper than bags. Wet soil weighs noticeably more, so check whether your supplier quotes by volume or by weight.
Working in feet and cubic yards
US landscape suppliers sell by the cubic yard. One cubic yard is 27 ft³, or 0.7646 m³. A raised bed of 10 ft × 4 ft × 1 ft holds 40 ft³, which is 40 ÷ 27 = 1.48 cubic yards. One cubic foot is about 28.3 litres, so a 1.5 ft³ bag holds roughly 42 litres. Use the cubic converter to switch between any of these units.
Choosing the right soil
Screened topsoil has stones and roots removed and suits lawns and general beds. Blended or “veg-grade” loam is mixed with composted organic matter and suits food growing. A practical mix for new vegetable or raised beds is about 70% topsoil to 30% well-rotted compost. Ask for soil that meets the British Standard for topsoil (BS 3882) in the UK, which sets limits on contaminants and stones. For raised beds, see our guide on how much topsoil a raised bed needs.