How the Paving Calculator Works
This calculator computes the area of your paved surface (either rectangular or circular), multiplies it by the specified depth or thickness, and then uses the material density to determine the total weight. Knowing the weight is essential when ordering asphalt or concrete from a supplier — they sell by the tonne, not by volume.
For pavers, the calculator uses a per-square-foot weight estimate rather than a volume-based density. Enter your paver dimensions to also calculate how many individual pavers you will need, including a 10% waste allowance for cuts at edges and breakage.
Material Densities Used
- Asphalt (hot mix): ~145 lb/cu ft (2,322 kg/m³) — standard dense-graded HMA.
- Concrete: ~150 lb/cu ft (2,403 kg/m³) — normal-weight unreinforced concrete.
- Gravel base: ~105 lb/cu ft (1,682 kg/m³) — compacted crushed stone sub-base.
- Concrete pavers: ~22 lb/sq ft (107 kg/m²) — typical 2-inch thick concrete paver.
- Clay brick pavers: ~10 lb/sq ft (49 kg/m²) — standard clay brick.
Typical Paving Depths and Applications
The correct depth depends on the intended use and traffic load. Under-spec paving cracks or sinks; over-spec wastes money. Use these general guidelines for residential projects:
- Asphalt driveway surface course: 2–3 inches over a 4–6 inch compacted gravel base.
- Concrete driveway: 4 inches (10 cm) for passenger vehicles; 6 inches for heavy trucks.
- Paver patio or walkway: 2.375 inch (60mm) pavers over 1 inch bedding sand over 4 inch compacted gravel base.
- Gravel driveway sub-base: 4–6 inches of compacted crusher run or crushed stone.
Frequently Asked Questions
How many tonnes of asphalt do I need per square metre?
A 50mm (2 inch) asphalt layer weighs approximately 112 kg per square metre. For a 75mm (3 inch) layer that rises to about 168 kg/m². Your supplier will quote a price per tonne, so this calculator's metric tonne output gives you exactly what you need for ordering.
How do I account for waste when ordering pavers?
This calculator automatically adds a 10% waste factor for paver counts. For complex patterns with many diagonal cuts, consider adding 15–20% instead. Always keep a few extra pavers from the same batch for future repairs, as colours can vary between production runs.
Do I need planning permission for a new driveway?
In most US jurisdictions, residential driveways do not require a permit unless they involve curb cuts onto a public road. In the UK, paving the front garden of a house generally requires planning permission unless a permeable surface is used. Always check your local council or municipality requirements before starting.