Planning guide
What is topsoil?
Topsoil is the upper, biologically active soil layer used to establish lawns, improve grades, and fill planting areas. Purchased blends vary in sand, silt, clay, and organic content.
How this calculation works
Volume equals surface area multiplied by finished depth. The optional material allowance helps cover small measurement differences, handling losses, and minor site variation. Soil can settle after placement, so confirm the finished depth or elevation for fill and grading work.
Choose an input for your project
Use finished depth and match the soil blend to the project.
| Project | Planning depth | Input check |
|---|---|---|
| Topdressing | Often 1/4–1/2 in | Avoid smothering existing turf |
| Lawn repair | Often 1–2 in | Measure low areas separately |
| New planting bed | Often 4–8 in | Existing soil and plant needs control depth |
Raised beds and grade changes should use their actual fill depth; large fills may need a different material beneath finish soil.
Common measurement mistakes
- Assuming every topsoil blend weighs the same
- Ignoring settlement after watering
- Adding a thick incompatible layer over poorly drained clay
Planning tips
- Choose screened soil for lawns and finish grading
- Loosen the existing surface before spreading
- Match the blend to drainage and planting needs
Topsoil Calculator FAQs
What topsoil depth should I use?
Lawn repairs often use 1–2 inches (2.5–5 cm); new beds commonly use 4–8 inches (10–20 cm) depending on the existing soil and intended plants.
How should I allow for topsoil settlement?
Topsoil can settle after spreading and watering, and the amount varies by soil blend and site conditions. For fill or grading work, confirm the finished depth or elevation after settlement and ask the supplier about expected loose-to-settled volume when needed.
Should I buy topsoil by the bag or in bulk?
Bags suit small repairs and constrained access. Bulk delivery is often more practical for larger beds and grading work, but supplier blend, density, and delivery minimums vary.