The Numbers
Weight Per Cubic Metre
| Condition | Weight per m³ |
|---|---|
| Dry screened topsoil | 1.1-1.3 tonnes |
| Moist screened topsoil (typical delivery) | 1.3-1.5 tonnes |
| Wet/saturated topsoil | 1.5-1.8 tonnes |
| Compacted topsoil (in the ground) | 1.5-1.7 tonnes |
The wide range exists because topsoil isn't a uniform product. Its weight depends on:
- Moisture content: The single biggest variable. Summer topsoil from a well-drained stockpile is at the lighter end. Winter topsoil after weeks of rain is significantly heavier
- Soil texture: Clay-heavy soil is denser than sandy soil. A cubic metre of clay loam weighs more than a cubic metre of sandy loam
- Organic matter content: Organic matter is lighter than mineral soil. High-organic garden soil blends weigh less than straight topsoil
- Screening: Screened topsoil with stones removed is slightly lighter than unscreened because stone is denser than soil
The working figure most suppliers and landscapers use is 1.4 tonnes per cubic metre. This is a reliable average for ordering, transport, and cost calculations.
Bulk Bag Weights
A standard bulk bag contains approximately 0.5-0.6m³ of topsoil:
| Bag size | Approximate weight |
|---|---|
| Small bag (0.25m³) | 350-450kg |
| Standard bag (0.5m³) | 700-900kg |
| Large bag (0.6m³) | 850-1,000kg |
| Jumbo bag (1.0m³) | 1,300-1,500kg |
Suppliers typically describe bags as "approximately 1 tonne" — this is a reasonable approximation for standard bags, though most are slightly under a full tonne. See our bulk bag guide for more on bag sizes and ordering.
Why Weight Matters
Vehicle Access
Delivery lorries carrying topsoil are heavy vehicles:
- A HIAB lorry carrying 4 bulk bags weighs 12-18 tonnes fully loaded
- A tipper lorry with a 10m³ loose load weighs 20+ tonnes
This matters if your road has weight restrictions, if there's a weak bridge on the access route, or if the lorry needs to cross a soft verge. See our delivery guide for full access advice.
Surface Protection
A single bulk bag concentrates 800-1000kg onto a roughly 1m × 1m footprint. That's 8-10 tonnes per square metre of pressure — enough to:
- Crack concrete paving slabs (most domestic slabs are rated for 3-5 tonnes per m²)
- Indent tarmac driveways (especially in warm weather when tarmac softens)
- Sink into gravel and become impossible to move
- Kill grass within 48 hours
Place bags on 18mm+ plywood to spread the load. On valuable surfaces, double up the plywood.
Collecting Yourself
If you're collecting topsoil from a quarry or supplier in a trailer or van, weight limits matter:
- A standard car trailer: 500-750kg capacity — roughly one bag maximum
- A 3.5-tonne van (transit-sized): 1,000-1,200kg payload — 1-2 bags
- A small tipper trailer: 1,500-2,500kg capacity — 2-3 bags
Overloading a vehicle is illegal (you'll be fined at a weighbridge check), dangerous (braking distances increase dramatically), and damaging to the vehicle. Always check your vehicle's payload rating.
Wheelbarrowing
The weight of topsoil determines how many wheelbarrow trips you'll need to move a delivery:
- A standard builders' wheelbarrow holds about 60-80 litres
- At 1.4 tonnes per m³, that's roughly 85-110kg per full load
- One bulk bag (0.5m³) = approximately 6-8 wheelbarrow loads of this weight
A full wheelbarrow of topsoil is heavy. If you're moving it any distance, especially uphill or over soft ground, half-fill the wheelbarrow to keep it manageable. Doubling the trips is faster than straining your back or tipping the barrow on a slope.
Volume vs Weight: The Ordering Confusion
Topsoil is sold by volume (cubic metres) or by weight (tonnes), and the two aren't interchangeable. This causes confusion when comparing prices between suppliers.
Example:
- Supplier A: "Bulk bag, 0.5m³" at £70
- Supplier B: "Bulk bag, approximately 0.85 tonnes" at £75
These are roughly the same amount of topsoil. Supplier B's weight-based description sounds like more, but 0.85 tonnes ÷ 1.4 (tonnes per m³) = 0.6m³. They're actually giving you slightly more.
Converting Between Volume and Weight
- Volume to weight: Multiply cubic metres by 1.4 (e.g., 3m³ × 1.4 = 4.2 tonnes)
- Weight to volume: Divide tonnes by 1.4 (e.g., 5 tonnes ÷ 1.4 = 3.6m³)
Use these conversions when comparing prices, calculating how much you need, or checking delivery weights.
Seasonal Weight Variation
The same volume of topsoil weighs noticeably different at different times of year:
- Spring/Summer: Drier, lighter, easier to move. Typically 1.2-1.4 tonnes per m³
- Autumn/Winter: Wetter, heavier, messier. Typically 1.4-1.6 tonnes per m³
This matters if you're storing topsoil — a pile that was manageable in summer becomes noticeably heavier after autumn rain. Cover stored topsoil to prevent water absorption.
It also matters for cost: some suppliers sell by weight, so a "1 tonne bag" delivered in winter may contain less volume than the same bag in summer, because the soil is heavier per unit volume.
The Bottom Line
The key number to remember: 1 cubic metre of topsoil weighs approximately 1.3-1.5 tonnes. Use 1.4 as your working figure. A standard bulk bag weighs roughly 800-1000kg. Plan your delivery access, surface protection, and moving strategy around these numbers, and you won't get any unpleasant surprises.