Topsoil Calculator

Topsoil volume is calculated by area (m²) multiplied by depth (mm). Under 2026 UK standards, apply a 15% natural settling factor to ensure final levels are met. Standard screened topsoil weighs ~1.6 tonnes per m³. For new lawns, a 100-150mm depth is recommended; raised beds require 200-300mm for optimal growth.

Enter Measurements

New lawns: 100-150mm. Raised beds: 200-300mm.
Natural Settling (%) 15%
The calculator will increase material volume by this amount to compensate for sinkage.
Please enter valid dimensions to calculate.

Results

Total Volume: 0.00 m³
Total Litres Needed: 0 L
Estimated Tonnes: 0.00 t

Delivery & Buying Options

Compare the most cost-effective ways to order your topsoil:

Option A
50L Small Bags
0
Individual Bags
Est: £0
Option B
Bulk Bags
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0.7m³ Volume Bags
Est: £0
Estimated Labour: 0.0 hrs
Expert Note: Results include your selected settling allowance. For bulk bags, we assume ~0.7m³ of screened soil per bag.
Removing old turf or soil? Use our Muck Away Calculator to estimate your disposal costs.
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Quick Topsoil Coverage Guide

How many m² does 1 tonne of topsoil cover? Use this reference table for standard depths:

Project Type Depth Coverage per Tonne
Top Dressing 10mm approx 60-70 m²
Lawn Levelling 50mm approx 12-15 m²
New Lawn / Turf 100mm approx 6-7 m²
Raised Beds 200mm approx 3 m²

Soil Layers Explained

TOPSOIL (100mm - 300mm)
Rich in minerals & organic matter
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SUBSOIL
Compact clay/sand layer
(Existing Ground)

Most UK garden projects involve adding a 100mm-200mm "Topsoil layer" above the existing subsoil to provide a nutrient-rich base for growth.

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How to Calculate Topsoil for Your Garden

Whether you're building raised beds, reviving a patchy lawn, or creating a new border, knowing exactly how much topsoil or compost you need is essential to avoid overordering or falling short.

Measuring Your Space

To calculate the required volume, simply measure the length and width of your area in metres. Then, determine the depth you need:

The Importance of the Settling Factor

Topsoil is naturally fluffy when first delivered. As it is watered and walked upon, it will compress. A standard organic topsoil can settle by up to 15-20%. Our calculator automatically factors in a settling percentage so your beds don't sink below your desired level after a few weeks.

Bags vs. Bulk Bags

Smaller projects might only require 50L bags to be carried through a house or into a tight garden. For larger projects, purchasing 800-1000kg bulk bags (jumbo bags) is far more economical and convenient. Remember that wet soil weighs significantly more than dry soil, which is why soil is often sold by volume (litres) rather than exact weight.

Topsoil Frequently Asked Questions

How much topsoil do I need?

To calculate your topsoil requirements, multiply the length and width of your area to get the square meterage (m²), then multiply by the desired depth (e.g., 0.1m for 100mm). This gives you the cubic volume. For example, a 50m² garden at 100mm depth requires 5m³ of topsoil.

How many m² does 1 tonne of topsoil cover?

One tonne of topsoil typically covers about 12 to 15 square meters (m²) at a standard depth of 50mm (2 inches). If you are laying a deeper base of 100mm, one tonne will cover approximately 6 to 7 m².

What is the difference between screened and unscreened topsoil?

Screened topsoil has been passed through a mesh to remove large stones, roots, and debris, resulting in a consistent, easy-to-work-with soil ideal for seeding and borders. Unscreened topsoil is raw soil that may contain larger rocks and is better suited for filling deep holes or as a base layer.

How many bulk bags of topsoil are in a tonne?

Most standard "Bulk Bags" (or "Jumbo Bags") in the UK are filled to approximately 0.6m³ to 0.7m³, which weighs roughly 850kg to 1 tonne depending on moisture content. Generally, one bulk bag is considered equivalent to one tonne for project planning.

Should I use topsoil or compost for my lawn?

Topsoil provides the structural base and mineral content for a lawn, while compost adds concentrated nutrients. For a new lawn, a mix of 70% topsoil and 30% compost is ideal. If you are just "top dressing" an existing lawn, a finely screened topsoil is preferred.

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BS 3882:2015 & Topsoil Quality

In the UK, the quality of topsoil is governed by British Standard BS 3882:2015. This standard ensures that the soil is fit for purpose and free from hazardous contaminants:

  • Multipurpose Topsoil: The most common grade, suitable for general landscaping, turfing, and domestic gardens.
  • Specific Purpose Topsoil: Soils tailored for acidic or alkaline-loving plants, or for low-fertility requirements (such as wildflower meadows).
  • Contamination Safety: Always ensure your supplier provides a 'Declaration of Compliance' or 'Soil Analysis Report' to confirm the soil is free from heavy metals or toxic substances.
  • pH Levels: Most garden plants prefer a pH between 6.0 and 7.0. BS 3882 requires suppliers to declare the pH and nutrient levels of the material.
Learn more about BS 3882:2015 Standards →