Calculating the total amount of material you will need for a project can sometimes be overwhelming. To help provide you with an estimate, we have put together this quick guide detailing how to calculate the amount of gravel you will need for your project.
Before you begin, think about the following:
| Project Type | Recommended Depth | Example Area (m²) | Volume Needed (m³) | Bags Required |
|---|---|---|---|---|
| Decorative garden borders | 30–40mm (3–4cm) | 10m × 3m = 30m² | 30 × 0.03 = 0.9m³ | 2 bags |
| Garden paths | 40–50mm (4–5cm) | 10m × 3m = 30m² | 30 × 0.04 = 1.2m³ | 2 bags |
| Driveways & parking areas | 50–100mm (5–10cm) | 10m × 3m = 30m² | 30 × 0.05 = 1.5m³ | 3 bags |
| Drainage & soakaway areas | 100–150mm (10–15cm) | 10m × 3m = 30m² | 30 × 0.10 = 3.0m³ | 5 bags |
1 Stoneworld bulk bag covers approx. 0.6m³
Always round up to ensure full coverage and account for surface settling.
The first step is to calculate the area of the section you would like to cover with gravel. The area calculation = A x B (Where A & B are 2 sides of a square or rectangular area).
For example, if your driveway measures 4m wide (A) by 12m long (B) the total area you need to cover is 48 sqm.
If you are looking to fill a driveway or path with gravel, we recommend the depth of the area should be 50mm thick as it will experience higher traffic. For covering planted areas, the depth only needs to be around 30mm thick.
Yes — gravel calculators are a useful tool when planning your project. They take the guesswork out of estimating how much gravel you need and help ensure you’re ordering the right amount the first time. Most calculators will ask you to input the length, width, and depth of your area and then generate an estimate based on those figures.
However, while calculators are convenient, they can only go so far. They often don’t account for irregular shapes, slopes, or ground conditions that may affect the actual volume required. That’s why it’s always a good idea to check your results with a professional — especially if you’re working on a larger or more complex project like a driveway or drainage system.
At Stoneworld, we’re happy to help. Whether you’re looking for a quick sanity check on your measurements or want us to calculate it for you, just get in touch. Our team can work from basic dimensions, sketches, or full landscaping plans to give you a reliable gravel quantity — and recommend the best type for your project.
The right gravel depends on how the area will be used:
We sell our gravel in 25kg polybags and in bulk bags. Based on our 20mm sized stones, 1 bulk bag of gravel will cover approximately 12 sqm at 50mm depth for paths and driveways. Alternatively, 1 bulk bag will cover approximately 16 sqm at 30mm depth. Our 25kg Polybags will roughly cover 0.4sqm.
Taking our earlier example into consideration, the total area needed to cover for the driveway was 48 sqm. Therefore, approximately 4 bulk bags would be required for 50mm depth.
Please be aware that this information can only be given as a rough guide due to the differing sizes of gravels, as this will lead to a slightly different coverage.
If you are still not sure how much gravel you will need, please call us on 01844 279274 or email us at sales@stoneworld.co.uk for any further advice you require. Our knowledgeable staff are always on hand for tips and advice. Alternatively, you can fill in the enquiry form below and one of our team will be in touch shortly.
