Soil calculator, mulch calculator and gravel calculator
Soil, mulch and crushed rock calculator (tonnes and m³)
Turn your length, width and depth into cubic metres and tonnes, then send the result straight into a quote request. We double-check the numbers when we quote.
How it works
To work out how much you need, multiply length by width by depth in metres to get cubic metres. Crushed rock is sold by the tonne at about 1.5 tonnes per cubic metre, so 4 m³ is about 6 tonnes. Soil and mulch are sold by the cubic metre. Allow extra for compacted bases.
Volume
4m³
About 6 tonnes.
Get a price for thisA rough guide only. Density changes with the quarry, the moisture and how much it compacts, so allow extra for compacted bases.
Cubic metres to tonnes
Rock and toppings are sold by the tonne, so the volume is converted with a rough density. These are the same figures the calculator uses.
Soil, mulch and most drainage rock, scoria and river pebbles are sold by the cubic metre, so no conversion is needed: order the volume. Each product shows its unit on the price list.
| Volume | Crushed rock (about 1.5 t per m³) | Aggregates and toppings (about 1.4 t per m³) |
|---|---|---|
| 1 m³ | 1.5 tonnes | 1.4 tonnes |
| 2 m³ | 3 tonnes | 2.8 tonnes |
| 4 m³ | 6 tonnes | 5.6 tonnes |
| 5 m³ | 7.5 tonnes | 7 tonnes |
| 8 m³ | 12 tonnes | 11.2 tonnes |
| 10 m³ | 15 tonnes | 14 tonnes |
| 20 m³ | 30 tonnes | 28 tonnes |
| 40 m³ | 60 tonnes | 56 tonnes |
What fits on each truck
Rock is carried by weight, soil and mulch by volume. Bigger loads mean fewer trips and lower freight per tonne.
A tandem load of crushed rock is roughly 8 m³ at about 1.5 tonnes per cubic metre.
| Truck | Rock | Soil | Mulch |
|---|---|---|---|
| Tandem tipper | 12 tonnes | 10 m³ | 10 m³ |
| Truck and trailer | 32 tonnes | 26 m³ | 26 m³ |
| Semi B-double | 60 tonnes, around 40 m³ | 70 to 80 m³ | 80 to 100 m³ |
Common questions
How many tonnes of crushed rock do I need?
Multiply length by width by depth, all in metres, to get cubic metres, then multiply by 1.5 for tonnes. A 10 m by 4 m area at 100 mm deep is 4 m³, or about 6 tonnes. Allow extra for compacted bases. The minimum crushed rock order is 5 tonnes.
How much soil do I need?
Soil is sold by the cubic metre. Multiply the area in square metres by the depth in metres: 20 m² of garden bed at 150 mm needs 3 m³. One cubic metre covers 10 m² at 100 mm deep. See garden soil prices.
How much mulch do I need?
Mulch is sold by the cubic metre with a 5 m³ minimum. One cubic metre covers 10 m² at 100 mm deep, or 20 m² at 50 mm. Garden beds and mulch are often laid 50 to 100 mm deep. See mulch prices.
How many cubic metres is a tonne of crushed rock?
At about 1.5 tonnes per cubic metre, one tonne of crushed rock is roughly 0.67 m³. Density changes with the quarry, the moisture and how much it compacts, so treat it as a guide.
How do I work out tonnes of gravel or toppings?
The calculator uses about 1.4 tonnes per cubic metre for aggregates and toppings, so 5 m³ is about 7 tonnes. Most rock and toppings have a 5 tonne minimum. Most drainage rock, scoria and river pebbles are sold by the cubic metre instead.
How much fits on a truck?
A tandem tipper carries 12 tonnes, or 10 m³ of soil or mulch. A truck and trailer carries 32 tonnes, or 26 m³ of soil or mulch. A semi B-double carries 60 tonnes of rock, around 40 m³.
Prices for the materials
Every price is per tonne or per cubic metre including GST. Delivery is quoted to your address before you order.
Got your numbers? Get your delivered price
Tell us what you need and where it is going. We confirm the total, delivery included, before anything is loaded.