Coverage Rate Calculator — Material Quantities by Area
Calculate how much material you need based on coverage rates.
How We Calculate This
Volume = Area x Depth. The depth is converted from millimetres to metres before multiplying.
For materials sold by weight, the volume is multiplied by the material density to give tonnes.
For materials sold in bulk bags, volume is divided by the standard 0.85 m³ bag size. The optional 10% wastage covers uneven spreading.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.