Calculate Your Topsoil
Choose your area shape, enter dimensions and topsoil depth. We calculate volume, bag counts, bulk bags, weight and estimated cost.
Your Topsoil Results
Estimated Cost (2026 UK Prices)
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How Much Topsoil Do I Need?
The formula is simple: Length (m) x Width (m) x Depth (m) = Volume (m³). Multiply by 1,000 to convert to litres. The tricky part is knowing the right depth for your project, which is why we built this topsoil calculator with recommended depths built in.
A small raised bed needs surprisingly large volumes. A standard 2.4m x 1.2m bed at 30cm deep requires 864 litres -- that is 35 bags of 25-litre topsoil or a full bulk bag. Most people underestimate by at least 30%, which means a second delivery charge and a frustrating delay mid-project.
This calculator handles rectangles, circles and L-shaped areas. It gives you results in cubic metres, litres, 25L bags, 40L bags, bulk bags (850 litres) and approximate weight in tonnes. It also estimates cost at 2026 UK prices so you can budget before ordering.
Worked Example: Raised Bed
A 2.4m x 1.2m raised bed filled to 30cm deep:
- Area: 2.4 x 1.2 = 2.88 m²
- Volume: 2.88 x 0.30 = 0.86 m³
- Litres: 0.86 x 1,000 = 864 litres
- 25L bags: 864 ÷ 25 = 35 bags (at £5 each = £175)
- Bulk bags: 1 bulk bag (at £65 delivered = £65)
The bulk bag saves £110 on a single raised bed. For multiple beds, the savings compound rapidly.
Worked Example: New Lawn
A 6m x 4m lawn area prepared to 15cm depth for grass seed:
- Area: 6 x 4 = 24 m²
- Volume: 24 x 0.15 = 3.6 m³
- Litres: 3,600 litres
- Bulk bags: 3,600 ÷ 850 = 5 bulk bags
- Weight: 3.6 x 1.2 = 4.3 tonnes
At this volume, ask your supplier about a loose tipper delivery -- it is typically £35-50 per cubic metre versus £65-80 per bulk bag. Once the topsoil is down, use our grass seed calculator to work out the right seeding rate.
Recommended Topsoil Depths
Not sure how deep to fill? These are the recommended topsoil depths for the most common UK garden projects, based on horticultural best practice.
| Project | Depth (cm) | Depth (inches) | Notes |
|---|---|---|---|
| Raised bed (vegetables) | 25–30 | 10–12 | Deep enough for most crops including tomatoes and beans |
| Raised bed (root veg) | 30–45 | 12–18 | Carrots, parsnips and potatoes need the full depth |
| Flower border | 15–20 | 6–8 | Sufficient for bedding plants and most perennials |
| New lawn (seed) | 10–15 | 4–6 | 15cm gives much better drought resistance than 10cm |
| New lawn (turf) | 5–10 | 2–4 | Turf brings its own root zone -- less topsoil needed |
| Lawn top-dressing | 1–2 | ½–1 | Thin layers only -- thicker smothers the grass |
| Lawn levelling | 2–5 | 1–2 | Use fine screened topsoil to fill hollows |
| Tree planting pit | 45–60 | 18–24 | Backfill with a 75/25 mix of topsoil and compost |
Settlement allowance: Fresh topsoil settles by 10–15% in the first few weeks. If you need a finished depth of 30cm, fill to 33–35cm initially. The calculator gives you the volume for your target depth -- add 10–15% on top to account for this.
Topsoil Types for Different Projects
Not all topsoil is the same. The type you buy should match your project. Here are the main types available in the UK and where each one works best.
General Purpose Screened Topsoil
Natural soil passed through a 10–20mm mesh to remove stones, roots and debris. This is the standard option for most garden projects -- borders, raised beds, lawn preparation and general landscaping. Quality varies between suppliers, so always ask whether it has been screened and what the source is. Expect to pay £50–70 per bulk bag delivered.
Premium BS 3882 Topsoil
Independently laboratory-tested for pH, organic matter content, stone percentage and contamination. BS 3882 is the British Standard for topsoil quality, and any reputable bulk supplier should be able to show you the certificate. Premium grade is the best choice for vegetable beds and new lawns where soil quality directly affects results. Budget £70–100 per bulk bag.
Sandy Loam Topsoil
The ideal soil texture for most plants. Sandy loam drains freely, warms up quickly in spring, and is easy to work even after rain. If your garden sits on heavy clay, importing sandy loam for raised beds transforms growing conditions. Particularly good for root vegetables, herbs and Mediterranean plants. Typically £80–110 per bulk bag.
Blended Raised Bed Topsoil
Pre-mixed topsoil and compost (usually 60/40 or 70/30 blend) sold specifically for filling raised beds. The advantage is convenience -- you fill and plant without mixing. The downside is cost: £90–120 per bulk bag versus £65–70 for plain topsoil plus £30–40 for a bag of compost to mix yourself. For small projects it saves time; for larger orders, mixing your own is significantly cheaper.
| Topsoil Type | Price per Bulk Bag | Best Use |
|---|---|---|
| General Purpose (screened) | £50–70 | Borders, lawns, general landscaping |
| Premium BS 3882 | £70–100 | Vegetable beds, fine lawns |
| Sandy Loam | £80–110 | Clay gardens, root veg, drainage |
| Blended Raised Bed | £90–120 | Raised beds (ready to plant) |
| Unscreened (budget) | £30–50 | Backfilling, raising ground levels |
Planning to mix your own raised bed soil? Use the calculator above for the total volume, then split your order: 60% topsoil and 40% compost. Mix them as you fill the bed. This is cheaper and gives you control over quality.
Bags vs Bulk Bags -- When to Order in Bulk
The way you buy topsoil affects the final cost more than the type of soil you choose. Here is a straightforward price comparison for 2026 so you can pick the right option.
| How You Buy | Volume | Typical Price | Cost per m³ |
|---|---|---|---|
| 25L bags (garden centre) | 25 litres | £4–7 per bag | £160–280 |
| 40L bags (garden centre) | 40 litres | £5–8 per bag | £125–200 |
| Bulk bag (delivered) | 850 litres | £50–100 delivered | £60–120 |
| Loose tipper load | 3+ m³ | £35–50 per m³ | £35–50 |
The crossover point
For anything under 200 litres (8 bags of 25L), individual bags from a garden centre or Amazon are the simplest option. Between 200 and 2,500 litres, bulk bags are the sweet spot -- cheaper per litre than bags and most suppliers deliver for a flat fee. Above 3 cubic metres (3,000 litres), ask about loose tipper delivery. It is the cheapest per-tonne option but requires vehicular access and a place to dump the heap.
Delivery considerations
Bulk bags weigh close to a tonne. The delivery driver uses a crane or forklift to place the bag, so you need a firm surface within reach of the lorry -- a driveway or paved area works well. Soft lawn does not: the weight will leave a deep depression. If your only access is through a side gate, measure the width first. Most bulk bags are 90cm x 90cm and will not fit through a standard 75cm gate. In that case, individual bags carried by hand may be the only practical option despite the higher cost.
How Many Bags of Topsoil for a Raised Bed?
Raised beds are the single most common reason people use this topsoil calculator. Here are the exact quantities for popular UK raised bed sizes, calculated at a standard 30cm fill depth.
| Raised Bed Size | Volume Needed | 25L Bags | 40L Bags | Bulk Bags |
|---|---|---|---|---|
| 1.2m x 0.6m (4ft x 2ft) | 216 litres | 9 | 6 | — |
| 1.2m x 1.2m (4ft x 4ft) | 432 litres | 18 | 11 | 1 |
| 1.8m x 0.9m (6ft x 3ft) | 486 litres | 20 | 13 | 1 |
| 2.4m x 1.2m (8ft x 4ft) | 864 litres | 35 | 22 | 1 |
| 3.0m x 1.2m (10ft x 4ft) | 1,080 litres | 44 | 27 | 2 |
| 3.6m x 1.2m (12ft x 4ft) | 1,296 litres | 52 | 33 | 2 |
Money-saving tip: For any bed needing more than 500 litres, a bulk bag at £65 delivered is dramatically cheaper than individual bags. A 2.4m x 1.2m bed filled with 25L bags costs roughly £175; the same volume in a bulk bag costs £65. That is a £110 saving on one bed alone.
Want the exact soil mix breakdown including compost and drainage material? Use our dedicated raised bed soil calculator which handles L-shaped layouts and shows the 60/30/10 mix split.
Topsoil Coverage Calculator -- Litres Per Square Metre
A quick-reference table showing how much topsoil covers one square metre at different depths. Useful for estimating before you measure.
| Depth | Litres per m² | Tonnes per m² | Typical Use |
|---|---|---|---|
| 2cm | 20 litres | 0.024 t | Lawn top-dressing |
| 5cm | 50 litres | 0.06 t | Lawn levelling, bed refresh |
| 10cm | 100 litres | 0.12 t | Shallow borders, turf prep |
| 15cm | 150 litres | 0.18 t | New lawns, flower beds |
| 20cm | 200 litres | 0.24 t | Deep borders, shrub planting |
| 30cm | 300 litres | 0.36 t | Raised beds, vegetable growing |
| 45cm | 450 litres | 0.54 t | Deep raised beds, root crops |
Weight conversion: Topsoil weighs approximately 1.2 tonnes per cubic metre when loose and dry. One tonne of topsoil is roughly 830 litres (0.83 m³). Wet topsoil after rain is significantly heavier -- up to 1.5 tonnes per cubic metre.
How Much Does a Bulk Bag of Topsoil Cover?
A standard bulk bag holds approximately 850 litres (0.7–0.85 m³) and weighs 800–1,000 kg. Here is how far one bulk bag stretches at different depths.
| Depth | Area Covered by 1 Bulk Bag | Typical Project |
|---|---|---|
| 5cm | 17 m² | Top-dressing a small lawn |
| 10cm | 8.5 m² | Shallow border or turf preparation |
| 15cm | 5.7 m² | New lawn from seed |
| 20cm | 4.3 m² | Flower border |
| 30cm | 2.8 m² | Single raised bed (2.4m x 1.2m) |
As you can see, a bulk bag does not go as far as most people expect -- especially at raised bed depths. A single 2.4m x 1.2m bed almost uses an entire bulk bag. If you are filling multiple beds, order accordingly and always round up.
Frequently Asked Questions
Best Topsoil Products UK 2026
Whether you are filling raised beds or preparing a new lawn, these are the top-rated topsoil products you can buy in the UK right now.
| Product | Size | Best For | Buy |
|---|---|---|---|
| Westland Multi-Purpose with John Innes | 60L | Raised beds -- the UK's top-selling compost mix | Amazon |
| Rolawn Blended Loam Topsoil | Bulk bag (1m³) | Best bulk topsoil -- screened, weed-free, BS 3882 | Amazon |
| Miracle-Gro Raised Bed Soil | 42L | Pre-mixed raised bed soil -- fill and plant | Amazon |
| Horticultural Grit (Coarse) | 25kg | Drainage improvement for clay soils and herb beds | Amazon |
| Soil pH Test Kit | Kit | Test before planting -- avoid pH problems | Amazon |
| Coco & Coir Rose, Tree & Shrub Compost | 40L | Peat-free planting compost -- blends with topsoil | Coco & Coir |
Links above are affiliate links -- we may earn a small commission at no extra cost to you.
Where to Buy — Organic Topsoil UK 2026
We recommend organic and sustainably sourced products where possible. These links support GardenCalc at no extra cost to you.
- Organic Topsoil Bags — Gardening Naturally — screened, peat-free organic topsoil for raised beds, borders and lawns.
- Soil Improver — Gardening Naturally — blend with existing topsoil to boost fertility and drainage naturally.
- Bulk Topsoil Bags — Wilko — budget-friendly bagged topsoil for garden beds and landscaping projects.
Affiliate disclosure: links above help fund GardenCalc. We only recommend products we'd use ourselves.
Related Calculators
Planning a bigger project? These calculators work alongside the topsoil calculator to help you get every quantity right.
- Soil Calculator -- General soil volume calculator for all garden projects
- Compost Calculator -- Work out how much compost to mix with your topsoil
- Raised Bed Calculator -- Soil mix breakdown for raised beds including L-shapes
- Grass Seed Calculator -- Seeding rates for new lawns over fresh topsoil
- Mulch Calculator -- Bark mulch quantities for weed suppression after planting
- Turf Calculator -- How many turf rolls for your new lawn
- Fertiliser Calculator -- Feed your new topsoil at the right application rate