Scoria calculator
Work out how much scoria a drainage layer or garden bed needs.
Scoria calculator
Use your supplier's density
You need
- Volume
- Weight
- Area
| Order by | Exact | Order, rounded up for anything sold in whole bags |
|---|
Enter your measurements to see what to order.
One cubic metre of scoria weighs about 0.93 tonnes and covers about 20 square metres at 50mm.
How to work out how much scoria you need
- Measure the area in metres and multiply length by width.
- Pick a depth in mm and multiply it by the area to get a volume.
- Multiply the volume by the bulk density, 925 kg per cubic metre for scoria, to get a weight.
- Divide the weight by your supplier's tonne or bulk bag to get what to order, and round up. Suppliers do not sell part bags.
- Add 10 percent. Covers settlement, uneven ground and the material lost around the edges. A second delivery for half a yard costs more than the extra you did not use.
How many tons in a cubic yard of scoria?
About 0.78 US tons, at 925 kg per cubic metre. Because published densities run from 850 to 1000, the honest answer is a range: between 0.72 and 0.84 tons per cubic yard depending on grading and how wet the load is.
How many cubic yards in a ton of scoria?
About 1.28 cubic yards. One tonne is about 1.08 cubic metres.
How much does scoria weigh?
Between 850 and 1000 kg per cubic metre, a spread of 18 percent. The lightest aggregate on the site. Volcanic and full of voids. The calculator above uses 925, and you can replace it with your own supplier's figure.
3 published figures from 3 suppliers, read 2026-09-20.
| Supplier | Published figure | Condition |
|---|---|---|
| Australian Native Landscapes (ANL)AU | 1.0 tonnes per cubic metre | loose |
| Landscape Design Institute (LDI) industry bulk density chart, Rev 10 July 2020AU | 0.85 T/m3 loose density (stockpile), 1.00 T/m3 compacted density, for 10mm and 20mm scoria | loose (stockpile) and compacted |
| Parklea Sand and Soil (Sydney)AU | cubic metres x 1 = tonnes (i.e. 1 tonne per cubic metre) | unstated |
What you can order scoria in
| Pack | Where | Size |
|---|---|---|
| cubic metre | UK, AU | 1 m3 |
| tonne | UK, AU | 1,000 kg |
| scoop (0.5 cubic metre) | AU | 0.5 m3 |