Soil Volume Calculator UK

Measure the length and width of the area in metres, decide on a depth in centimetres, and multiply length × width × depth (converted to metres) to get cubic metres. This calculator does that automatically and also converts the result into tonnes, bulk bags and small bags.

Roughly 1.3 to 1.7 tonnes, depending on how moist and compacted the soil is. A commonly used trade average is 1.5 tonnes per cubic metre, which is the default this calculator uses — adjust it if your supplier quotes a different figure.

It depends on the bag size and how deep you're spreading. A typical 0.8m³ bulk bag covers about 8m² at 10cm depth, or roughly 2.7m² at 30cm depth. Bulk bags range from around 0.6m³ to 0.8m³ depending on the supplier, so always check the exact size.

For most vegetables, aim for at least 30–45cm of topsoil depth. A 2m × 1m bed at 45cm needs roughly 0.9m³ before settlement allowance. Shallow-rooted crops like salad leaves and strawberries can manage with around 30cm.

For seeding or turfing over reasonable existing ground, 10cm of topsoil over loosened subsoil is a common minimum. On poor or compacted ground, more depth and proper subsoil preparation will give better long-term results.

Yes — freshly delivered topsoil contains air pockets and will compact after rain, watering and foot traffic. A 10% allowance is a widely used starting point; heavier, wetter soil or a very uneven base may need 15–20% extra.

Topsoil is the nutrient-rich upper layer where most plant roots and biological activity are concentrated. Subsoil sits beneath it, is denser and less fertile, and is used to build up levels rather than to grow in directly. Compost is organic matter added to either to improve structure and nutrients — it is not a substitute for bulk topsoil volume.

A 0.8m³ bulk bag holds 800 litres; a 0.6m³ bag holds 600 litres. Always check your supplier's stated bag volume, since "bulk bag" is a generic term for a large woven tote rather than a fixed UK size.

For small projects (under roughly 1m³) bagged or a single bulk bag is usually more practical. For larger projects, loose bulk delivery by tipper lorry is typically the most cost-effective option per cubic metre, though it needs vehicle access and space to tip the load.

Yes, many gardeners blend topsoil with compost or well-rotted manure (often around 25–50% by volume) to improve fertility and structure, particularly for raised beds and containers. Calculate the topsoil portion first, then add your chosen proportion of compost on top.

Use the circular shape option and enter the diameter. The calculator applies π × (diameter ÷ 2)² × depth to get the volume in cubic metres, the same principle as the rectangular calculation but for a round area.

BS 3882:2015 is the current British Standard specification for topsoil in the UK. It covers grading and quality, including that individual topsoil layers should not normally exceed 300mm, topped up with loosened subsoil to reach a minimum rooting depth of 450mm for grass or 600mm for other planting.

Freshly laid topsoil typically settles noticeably within the first few weeks, especially after rain or watering, and continues to consolidate gradually over several months. This is why ordering slightly more than the raw calculated volume is standard practice.

For anything beyond a small container, pure compost is usually too rich, too free-draining and too expensive to use as bulk fill. Topsoil provides the structural bulk and mineral content plants need, with compost mixed in as an enrichment rather than the main volume.

That depends entirely on depth: at 10cm depth you need 0.1m³ per m², at 30cm depth you need 0.3m³ per m², and at 45cm depth you need 0.45m³ per m². Multiply your area in m² by your chosen depth in metres to get cubic metres.

No. This tool gives an estimate only and is not landscaping, structural, or waste-disposal advice. Actual quantities vary by supplier bulk density, moisture content and site conditions, so confirm exact figures with your supplier before ordering.