Gravel Calculator
Calculate gravel or aggregate volume, weight and cost for a given area and depth.
Please note: Material estimates for planning only. Always confirm quantities against your drawings, local building codes and supplier specifications before ordering. Structural work requires a qualified engineer.
What the Gravel Calculator does
Gravel is sold by weight but specified by the area and depth you want to cover. Volume times bulk density gives the tonnage — and because density varies considerably between materials, using the right figure matters.
Formula
Area = Length × Width, or π × (Diameter ÷ 2)² for a circleVolume = Area × Depth × (1 + Waste %)Tonnes = Volume × Density ÷ 1,000
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Area shape | one of 2 options | Yes | — |
| Length | number | In some modes | Accepts more than 0. Shown Area shape is Rectangular. |
| Length unit | one of 6 options | In some modes | Shown Area shape is Rectangular. |
| Width | number | In some modes | Accepts more than 0. Shown Area shape is Rectangular. |
| Width unit | one of 6 options | In some modes | Shown Area shape is Rectangular. |
| Diameter | number | In some modes | Accepts more than 0. Shown Area shape is Circular. |
| Diameter unit | one of 6 options | In some modes | Shown Area shape is Circular. |
| Depth | number | Yes | Accepts more than 0. |
| Depth unit | one of 5 options | Yes | — |
| Gravel density | kg/m³ | Yes | Accepts 100 or more. |
| Waste allowance | % | Yes | — |
| Price per tonne | selected currency | Optional | Accepts 0 or more. |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose Area shape and Depth unit.
- Enter Depth, Gravel density and Waste allowance.
- Fill in the remaining inputs the form shows for your choice.
- Optionally add Price per tonne.
- Select Calculate.
Worked example
An 8 m × 3 m area at 50 mm depth, 1,680 kg/m³ gravel, 5% waste.
- Length
- 8 m
- Width
- 3 m
- Depth
- 50 mm
- Density
- 1680
Area 24 m², volume 1.2 m³, with waste 1.26 m³ → 2.12 tonnes.
Frequently asked questions
How deep should gravel be?
50 mm for decorative cover, 100 mm for a path, and 150–200 mm of compacted sub-base under a driveway.
How much area does a tonne cover?
Roughly 12 m² at 50 mm depth for typical gravel. The calculator shows this for your chosen density and depth.