Formula used
Rectangular area: Area = Length × Width.
Circle area: Area = π × Radius².
Ring area: Area = π × (Outer Radius² − Inner Radius²) × Angle ÷ 360.
Base gravel volume: Volume = Total Area × Gravel Depth.
Adjusted volume: Final Volume = Base Volume × (1 + Compaction %) × (1 + Waste %) × (1 + Ground Correction %).
Estimated weight: Weight = Final Volume × Gravel Density.
Bag count: Bags = Round Up(Required Weight ÷ Bag Weight), checked against bag volume.
Total project cost: Gravel + Delivery + Labour + Sub-base + Fabric + Edging + Tax.
How to use this calculator
- Add every path section and select its shape.
- Enter dimensions and choose the correct measurement unit.
- Select the gravel type, depth, compaction, and waste allowance.
- Enter supplier bag sizes, prices, delivery charges, and labour.
- Enable sub-base, fabric, edging, or product comparison when required.
- Select Calculate to review quantities, purchase recommendations, and costs.
Recommended gravel depths
| Application | Typical depth | Guidance |
|---|---|---|
| Light decorative cover | 25–30 mm | Suitable where foot traffic is limited. |
| Standard garden path | 40–50 mm | Common depth for comfortable pedestrian use. |
| Durable high-use path | 50–75 mm | Better resistance to displacement and settlement. |
| Deep decorative aggregate | 75–100 mm | Use only where the design requires extra depth. |
Example calculation
| Input | Example value |
|---|---|
| Path dimensions | 10 m × 1.2 m |
| Gravel depth | 50 mm |
| Gravel density | 1,650 kg/m³ |
| Compaction allowance | 10% |
| Waste allowance | 10% |
| Approximate final volume | 0.726 m³ |
| Approximate final weight | 1,198 kg |
Frequently asked questions
How deep should gravel be for a garden path?
Most pedestrian garden paths use 40–50 mm of gravel. Heavier use may require 50–75 mm.
Should I include a sub-base?
A compacted sub-base improves stability and drainage. It is especially useful on soft or frequently wet ground.
Why does gravel density matter?
Density converts volume into weight. Different aggregates can produce different order weights for the same path volume.
What waste allowance should I use?
Five to ten percent is common. Irregular edges, spillage, and uneven ground may justify a larger allowance.
How are curved paths calculated?
Curved paths use ring geometry. Enter the inner radius, outer radius, and covered angle.
Can I calculate several paths together?
Yes. Add separate path sections and the calculator combines their areas and perimeters.
How does the calculator estimate bag quantities?
It checks both bag weight and bag volume. The larger rounded requirement is used.
Does the total include delivery and labour?
Yes. Enter delivery, labour, optional materials, and tax to create a broader project estimate.
Can I compare bagged and loose gravel?
Use the price basis and product comparison options. This helps compare supplier pricing methods.
Are the density presets exact?
No. They are planning estimates. Use the supplier density whenever it is available.