Topsoil calculator
Estimate topsoil for lawns, borders and raised beds in litres, cubic metres or cubic yards — with the settlement allowance that stops beds sinking.
Your project
Quick start
Beds and areas
Add one section per bed. Rectangles for raised beds, circles for round borders, and subtract anything already planted.
Depth and soil type
100–150 mm for a new lawn, 300 mm or more for vegetable beds.
General-purpose soil to BS 3882 multipurpose grade.
Raised beds are filled to the internal height and settle more than open ground.
Freshly tipped soil drops as it is watered and worked. 20% is a sensible default.
How you will buy it
Topsoil bulk bags are quoted by volume, typically 0.7–0.8 m³.
Covers spillage during barrowing and soil left in the bag.
Estimate updated. 4 bulk bags of Screened topsoil required.
Topsoil calculator
United Kingdom · Metric units · 30 July 2026
Shopping list
1 line- 4bulk bagsScreened topsoil150 mm depth over 15.00 m² (161.46 ft²)
Estimate results
What you measured
- Area
- 15.00 m²
- 161.46 ft²
- Depth
- 150 mm
- Volume to order
- 2.70 m³ (3.53 yd³)
- 2,700 L
- Cubic metres
- 2.70 m³
What to buy
5% waste included| Material | Buy | Weight |
|---|---|---|
Screened topsoil 150 mm depth over 15.00 m² (161.46 ft²) Rounding: The calculation requires 3.7 bulk bags. Adding 5% waste gives 3.88. Rounded up to 4 bulk bags. Main material | 4bulk bags | 3,796 kg |
Assumptions behind each line
Screened topsoil
- Density taken as 1,300 kg/m³ (range 1,100–1,500).
- A 20% settlement allowance is added before rounding.
- Topsoil bulk bags are quoted by volume, typically 0.7–0.8 m³.
Beds and fill depth
How this was calculated
Area
plus Main area (5 × 3 m) = 15.00 m²
= 15.00 m² (161.46 ft²)
Finished volume
15.00 m² (161.46 ft²) × 150 mm depth
= 2.25 m³ (2.94 yd³)
Volume to order
2.25 m³ (2.94 yd³) × 1.20 (20% settlement)
= 2.70 m³ (3.53 yd³) — 2,700 L
- Soil consolidates once it is watered and walked on. Order for the settled depth you want, not the depth on the day it arrives.
Approximate delivered weight
2.70 m³ (3.53 yd³) × 1,300 kg/m³
= 3.51 tonnes (7,738 lb)
Purchase quantity
The calculation requires 3.7 bulk bags. Adding 5% waste gives 3.88. Rounded up to 4 bulk bags.
= 4 bulk bags
Weight and delivery
Approximate weight
3.80 tonnes
Likely delivery
tipper or grab lorry
- Loose soil is usually tipped on the driveway. Have boards or a tarpaulin down first and a route for the barrow.
- 3.80 tonnes needs a tipper or grab lorry. Confirm access width, overhead clearance and where the driver can tip.
- Check that the delivery route can take the weight — block paving, drainage covers and soft verges are easily damaged.
Note: Soil settles
Data behind this estimate
| Assumption | Value | Source |
|---|---|---|
Screened topsoil Screened, moist topsoil. Very wet soil can exceed 1,500 kg/m³. | 1,300 kg/m³range 1,100–1,500 | British Standards InstitutionReviewed 2026-07-01 |
Topsoil settlement allowance Freshly tipped soil settles as it is watered and worked. Raised beds settle most. | 20 %range 10–25 | British Standards InstitutionReviewed 2026-07-01 |
Default waste allowance Covers cutting, breakage, setting-out error and the odd unusable unit. | 10 %range 5–15 | Project EstimateReviewed 2026-07-01 |
Cost
Enter the prices your supplier quoted. This site does not hold or estimate supplier prices, so totals appear only once you fill these in.
UK standard-rate VAT is 20%. Builders' merchant prices are often quoted excluding VAT.
No prices entered yet. Everything else in this estimate — quantities, weight, delivery and the shopping list — works without them.
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How this calculator works
Every figure below is derived rather than looked up, so you can check it against your own numbers. Nothing is hidden behind a black box.
Volume
Bed areas are summed, subtracted sections removed, and the total multiplied by the finished depth.
volume = total area × finished depth
Settlement
Tipped soil consolidates as it is watered and worked. The settlement allowance increases the ordered volume so the bed still reaches the depth you wanted once it has settled.
Twenty per cent is the default. Raised beds and organic blends justify more; a thin lawn dressing needs less.
ordered volume = finished volume × (1 + settlement %)
Litres and bags
UK topsoil bags are labelled in litres, so litres are shown alongside cubic metres. One cubic metre is 1,000 litres — which is why a 35 L bag covers so little ground and why bulk bags dominate above about a cubic metre.
Weight
Screened topsoil is taken as 1,300 kg/m³, blended topsoil 1,150 kg/m³ and soil/compost blends 800 kg/m³. Very wet soil can exceed these figures by a fifth, which matters when you are checking whether a delivery can cross a driveway.
Common questions
- How much topsoil do I need for a new lawn?
- Aim for 100–150 mm (4–6 in) of good quality soil over a broken-up subsoil. Less than 100 mm dries out quickly and the grass struggles in a dry summer.
- How many litres are in a bulk bag of topsoil?
- UK topsoil bulk bags are typically 700–800 litres, commonly quoted as 730 L or 0.73 m³. They are sold by volume rather than weight because soil density varies so much with moisture.
- Why does my raised bed need more soil than the calculation says?
- Because soil settles. A 400 mm bed filled level on the day of delivery will typically sit 40–80 mm lower after a few weeks of watering. The settlement allowance covers this.