Topsoil Calculator UK
This topsoil calculator turns a length, width and depth into the volume of topsoil you need, displayed in the units UK suppliers actually sell in — cubic metres, tonnes, litres and bulk bags. It handles both rectangular and circular areas, and adds a wastage margin because ground settles, levels are never perfectly even, and a short delivery is always more inconvenient than a small surplus. Topsoil in the UK is sold loose by the cubic metre or tonne, and in bulk (dumpy) bags, which is why this calculator shows all three.
Enter a value greater than 0
Enter a value greater than 0
Allows for settling, uneven ground and compaction. 10% is typical for topsoil.
UK bulk (dumpy) bags are sold by weight or loose volume — sizes vary by supplier, so check before ordering.
Enter your dimensions above
to see your topsoil estimate
How to use this calculator
Pick your shape — rectangle for most lawns and beds, circle for round features. Choose whether to enter length and width directly, or type in the total area if you already know it. Select your units (metres is easiest for most jobs).
Set the depth. As a guide: 100–150 mm (10–15 cm) is the minimum for a new lawn from seed or turf over a firm sub-base; 200–300 mm for flower beds; 300–400 mm for raised vegetable beds. Leave the wastage at 10% unless you have a very flat, level site.
Choose your bulk bag size if you are buying bagged — the most common UK dumpy bag is 0.6 m³. Read off the result in cubic metres, litres, tonnes and bags.
Worked example — Rochdale back garden
A homeowner in Rochdale is levelling a back garden lawn measuring 8 m × 5 m and wants 100 mm (10 cm) of new topsoil.
Area = 8 × 5 = 40 m²
Depth = 0.10 m
Base volume = 40 × 0.10 = 4.0 m³
+10% wastage = 4.4 m³
≈ 4,400 litres
≈ 6.60 tonnes (at 1.5 t/m³)
≈ 8 bulk bags at 0.6 m³ each (4.4 ÷ 0.6 = 7.33 → round up to 8)
In practice, most UK topsoil suppliers deliver loose by the tonne or in dumpy bags. A full 8 m × 5 m lawn at this depth is usually a loose bulk delivery rather than bagged, since bagged topsoil works out dearer per m³ — see below.
Typical topsoil depths (UK guide)
| Use | Typical depth |
|---|---|
| Overseeding / top dressing an existing lawn | 10–25 mm |
| New lawn (seed or turf) | 100–150 mm |
| Flower beds / borders | 200–300 mm |
| Raised beds / vegetable plots | 300–400 mm |
| Tree / shrub planting pits | 400 mm+ |
Loose delivered vs bagged topsoil
Bulk (dumpy/bagged) topsoil almost always costs more per cubic metre than loose delivered topsoil. For anything above roughly 2–3 m³, a loose tipped load is usually cheaper — but you need somewhere to tip it and a way to barrow it to the bed or lawn. If access is tight, the road outside is your only option, or you simply need small quantities, bagged wins on convenience even if it costs more per m³.
Most calculator pages skip this trade-off entirely. The honest answer is: price both options from your local supplier before deciding, because the gap varies widely by region and season.
Topsoil grades — BS 3882:2015
BS 3882:2015 is the UK standard covering topsoil quality. It defines three grades: multipurpose, specific purpose and economy. For lawns and general landscaping, multipurpose grade to BS 3882 is the standard specification. Ask your supplier to confirm the grade — economy grade can carry more stones, roots and weed seeds, which matters a lot if you are seeding a lawn.
If a supplier cannot tell you the BS 3882 grade or quote a test certificate, that is worth knowing before you order several tonnes.
A note from the groundworks side
In practice, most people underorder topsoil because they forget it settles. Freshly tipped topsoil compacts by roughly 10–20% once it is spread, walked on and watered in — which is exactly why the wastage box defaults to 10%. A groundworker once told me his rule of thumb is to order a full tonne over on anything lawn-sized, because a second small delivery almost always costs more in delivery charges than the extra soil is worth.
A rough 2026 range for loose delivered screened topsoil in the UK is around £25–£45 per tonne for the soil itself, plus a delivery charge that can equal or exceed the soil cost for small orders. Bagged topsoil from a builders' merchant typically runs £5–£8 per 25-litre bag — that is equivalent to £200–£320 per cubic metre, compared with £40–£80 per cubic metre for a loose load. The difference matters once you are ordering more than 2–3 m³.
Frequently asked questions
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Guides worth reading
- How Much Topsoil Do I Need? UK Guide — depths, tonnes, bulk bags and 2026 prices explained
Disclaimer: Estimates only. Topsoil density, settling and supplier bag sizes vary — confirm quantities and grade (BS 3882) with your supplier before ordering.