Gravel, Sand & Aggregate Calculator (Tonnes & Yards)
Estimate the volume in cubic metres or yards and the delivered weight in tonnes or US tons of gravel, sand, road base, topsoil, or mulch to fill an area to a chosen depth.
Coverage area 30.0 m²; net volume before waste 3.00 m³. Weight is approximate (1.6 t/m³) — wet material is heavier and suppliers deliver to the nearest half-tonne or tonne.
How this works
Volume is area times depth; weight is volume times the material's bulk density:
volume = L × W × depth × (1 + waste%)
tonnes = volume(m³) × density(t/m³)
yd³ = volume(m³) × 1.308
US tons = tonnes × 1.1023Densities are typical loose-dry figures: gravel and sand ≈ 1.6 t/m³, road base ≈ 1.9, topsoil ≈ 1.3, bark mulch ≈ 0.4. Wet material is heavier — confirm against the supplier's ticket.
Worked example
A 10 m × 3 m driveway at 100 mm deep in gravel (1.6 t/m³), 10% waste/compaction:
- volume =
10 × 3 × 0.1 × 1.10= 3.3 m³ (≈ 4.32 yd³) - weight =
3.3 × 1.6= 5.28 tonnes (≈ 5.82 US tons)
Order to the next whole tonne or half-tonne your supplier delivers, and add a compaction allowance for sub-base layers.
Sources
- Typical aggregate bulk densities (Simetric material density tables; quarry product datasheets).
FAQ
How much gravel do I need?
Multiply the area you are covering by the depth of gravel to get a volume, then multiply that volume by the material's bulk density to get a weight, because gravel and sand are usually sold and delivered by the tonne. For example, a 10 m × 3 m driveway at 100 mm (0.1 m) deep is 3 m³; at a typical gravel density of 1.6 t/m³ that is about 4.8 tonnes. This calculator does both steps and adds a waste allowance.
How deep should a gravel layer be?
Depth depends on the use. A decorative gravel mulch over landscape fabric is often 40 to 50 mm (about 2 in). A gravel path is typically 50 to 100 mm, a pedestrian patio sub-base 100 mm, and a driveway sub-base 100 to 150 mm (4 to 6 in) or more over a compacted formation, sometimes in two layers of different stone sizes. For anything structural, follow the pavement or sub-base specification rather than a rule of thumb.
How many tonnes are in a cubic metre of gravel?
It depends on the material. Loose dry gravel and crushed stone are roughly 1.5 to 1.7 tonnes per cubic metre, sand about 1.6, road base or ballast around 1.9 to 2.1, topsoil about 1.3, and bark mulch only about 0.4. Wet material is heavier. This calculator uses typical loose-dry densities you can pick from a list; always check the supplier's ticket for the exact density of what you order.
Should I allow for compaction?
Yes, for sub-base and road-base layers. Loose aggregate compacts down when it is rolled or plate-compacted, so you need more loose material than the finished compacted volume — commonly 20 to 30 percent more for granular sub-base. Enter that as the waste/compaction allowance. Decorative gravel that is not compacted only needs a small allowance for spillage and settling.
How do cubic yards and tonnes relate?
They measure different things: cubic yards (or cubic metres) measure volume, while tonnes measure weight. Suppliers in the United States often quote gravel by the cubic yard, while UK, Australian, and Asian suppliers usually quote by the tonne. This calculator shows the volume in both cubic metres and cubic yards and the weight in both metric tonnes and US short tons so you can order in whichever unit your supplier uses.
Can I use this for a circular or irregular area?
This calculator assumes a rectangle (length × width). For a circular bed, multiply the radius by itself and by 3.14, and enter that as the area by setting one side to that value and the other to 1. For an irregular shape, break it into rectangles and triangles, work out each piece, and add them together. When in doubt, round the total area up — running short by a fraction of a tonne is a common and avoidable problem.