How Much Topsoil Do I Need? (Calculator + Guide)
By MasonryCalc ·
Too little topsoil and grass won’t establish. Too much and you’re paying for material that adds no benefit. Getting the depth right matters for both results and budget.
Whether you’re laying a new lawn, filling raised beds or top dressing an existing lawn, this guide gives you the formulas, depth recommendations and practical tips to get it right.
Skip the maths
Enter your dimensions and get instant results in cubic yards, cubic metres and tonnes.
Use the Topsoil Calculator →How Much Topsoil Do You Need?
The right depth depends on what you’re growing and how demanding the application is.
| Application | Min depth | Ideal depth |
|---|---|---|
| New lawn (seed) | 4 in / 100 mm | 6 in / 150 mm |
| New lawn (turf/sod) | 4 in / 100 mm | 6 in / 150 mm |
| Garden beds | 8 in / 200 mm | 12 in / 300 mm |
| Raised planters | 12 in / 300 mm | 18 in / 450 mm |
| Top dressing lawn | 0.5 in / 12 mm | 1 in / 25 mm |
| Filling low spots | As needed | Level with lawn |
Topsoil Calculator Formula
The calculation is straightforward — multiply length by width by depth, making sure all measurements are in the same unit first.
Volume (ft³) = Length (ft) × Width (ft) × Depth (ft)
Worked example — 10 × 10 ft lawn at 6 inch depth:
- Convert depth: 6 inches ÷ 12 = 0.5 ft
- Volume: 10 × 10 × 0.5 = 50 cubic feet
- Cubic yards: 50 ÷ 27 = 1.85 cubic yards
- Add 10% for settling: 2.0 cubic yards to order
Volume (ft³) = L × W × D
Cubic Yards = Volume ÷ 27
Cubic Metres = Volume × 0.0283How Is Topsoil Sold in the US?
Topsoil is sold by the cubic yard in the US — not by weight. Most landscape suppliers sell it loose, delivered by dump truck. A standard load is typically 10–15 cubic yards.
1 cubic yard covers:
| Depth | Area covered |
|---|---|
| 1 inch | 324 sq ft |
| 2 inches | 162 sq ft |
| 3 inches | 108 sq ft |
| 4 inches | 81 sq ft |
| 6 inches | 54 sq ft |
In the UK and Australia, topsoil is sold by the tonne or cubic metre. Bulk bags (approximately 0.7 m³) are common for smaller garden projects, while larger quantities are delivered loose by the cubic metre.
Types of Topsoil
Not all topsoil is the same. The right type depends on your application.
| Type | Best for | Notes |
|---|---|---|
| General purpose | Lawns, beds | Most common, widely available |
| Screened | Seedbeds, top dressing | Fine texture, weed-free |
| Sandy loam | Drainage-sensitive areas | Drains well, easy to work |
| Clay loam | Moisture-retaining beds | Heavy, holds nutrients well |
| Peat-free compost blend | Raised beds, planters | Rich, lightweight |
Tips for Buying Topsoil
- Always buy screened topsoil — unscreened can contain stones, roots and weed seeds that cause problems later.
- Check the pH — lawn topsoil should be pH 6.0–7.0. Ask your supplier if unsure.
- Order 10% extra for settling — topsoil compacts over time, especially after watering.
- Ask about the source — reputable suppliers can tell you where topsoil came from and confirm it’s contaminant-free.
- Bulk delivery saves money — for large lawns, bulk delivery by the yard is significantly cheaper than bagged topsoil from a garden centre.
Frequently Asked Questions
How many cubic yards of topsoil do I need for a 1,000 sq ft lawn?
At 4 inches deep you need approximately 12.3 cubic yards. At 6 inches deep you need 18.5 cubic yards. Use our topsoil calculator for any size.
How deep should topsoil be for a new lawn?
A minimum of 4 inches (100 mm) is needed for grass to establish properly. 6 inches (150 mm) gives better drought resistance and root development.
How much does a cubic yard of topsoil weigh?
Topsoil typically weighs 1,000–1,400 kg per cubic metre (1.4–1.9 US tons per cubic yard) depending on moisture content and composition.
How many bags of topsoil equal a cubic yard?
A standard 40 lb bag of topsoil contains approximately 0.75 cubic feet. You need roughly 36 bags to make one cubic yard. Bulk delivery is almost always more economical for anything over 10 bags.
Is topsoil the same as compost?
No — topsoil is the upper layer of natural soil and provides structure and minerals. Compost is decomposed organic matter that adds nutrients. For best results, mix topsoil with 20–30% compost.
Ready to calculate? Our topsoil calculator handles imperial and metric, shows results in cubic yards, cubic metres and tonnes, and includes the 10% waste recommendation automatically.