Topsoil Calculator
By Concrete Knowhow Editorial Team · Updated April 2024 · 4 min read
Quick Answer
Enter your area's length, width, and depth to get cubic feet, cubic yards, and the recommended order quantity — with a settling allowance so you don't end up short after the soil compacts.
Length
Width
Depth
Settling Allowance
Topsoil compacts 10–15% after delivery. Order extra so you end up at your target depth — not short.
Enter dimensions above to see results
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Common Coverage Areas — Quick Reference
“Order This Much” includes a 10% settling allowance.
| Area | Depth | Cubic Yards | Order This Much |
|---|---|---|---|
| 10×10 ft | 2" | 0.62 yd³ | 0.68 yd³ |
| 10×10 ft | 4" | 1.23 yd³ | 1.36 yd³ |
| 10×20 ft | 4" | 2.47 yd³ | 2.72 yd³ |
| 10×20 ft | 6" | 3.70 yd³ | 4.07 yd³ |
| 20×20 ft | 4" | 4.94 yd³ | 5.44 yd³ |
| 20×40 ft | 4" | 9.88 yd³ | 10.86 yd³ |
| 50×50 ft | 6" | 46.30 yd³ | 50.93 yd³ |
How to Spread Topsoil — Step by Step
- Test your existing soil. A basic soil test (available at garden centers) tells you pH and nutrient levels. Amend existing soil before adding topsoil where possible — it's cheaper than replacing it.
- Remove debris and weeds. Clear the area of rocks, roots, and existing vegetation. Till or loosen compacted areas to at least 4 inches to help new topsoil blend with native soil.
- Calculate and order. Use this calculator and add 10–15% for settling. Have it delivered as close to the project area as possible — topsoil is heavy to move by hand.
- Spread and grade. Distribute topsoil evenly with a rake. Work toward a slight slope away from foundations (6 inches per 10 feet) to direct drainage away from structures.
- Till the interface. Where new topsoil meets existing soil, till 2–3 inches deep to blend the layers. This prevents a hard boundary that can trap water or restrict root growth.
- Compact lightly. Use a lawn roller or your feet to gently firm the surface. Avoid heavy compaction — you want soil to be firm but still have air pockets for root development.
- Water thoroughly. Water the new topsoil to encourage settling and help it bond with underlying soil. You may need to top up low spots.
- Seed, sod, or plant. Wait 1–2 days after watering before seeding or laying sod so the surface firms up slightly. New plantings should be watered daily for the first 2 weeks.
Frequently Asked Questions
- How much topsoil do I need for a 10×20 ft lawn area at 4 inches deep?
- A 10×20 ft area at 4 inches deep is 66.7 cubic feet — about 2.47 cubic yards. With a 10% settling allowance, order 2.72 cubic yards to end up at your target depth after compaction.
- How deep should topsoil be for a new lawn?
- Grass roots need at least 4–6 inches of good topsoil. For a new lawn from seed or sod, aim for 4 inches minimum; 6 inches is better in compacted or poor native soil. Raised garden beds typically need 8–12 inches.
- Why do I need to order extra topsoil for settling?
- Bulk topsoil is loose when delivered and compacts 10–15% once watered in, walked on, and settled over time. If you order only the exact calculated amount, you will end up short of your target grade. Always add 10–15%.
- How much does a cubic yard of topsoil weigh?
- A cubic yard of dry topsoil weighs roughly 1,800–2,200 lbs depending on its composition and moisture content. Wet topsoil can weigh over a ton per cubic yard.
- What is the difference between topsoil and fill dirt?
- Topsoil is the upper 2–8 inches of earth, rich in organic matter and nutrients — it supports plant growth. Fill dirt is subsoil used to fill voids or raise grade, contains little organic matter, and should never be used as a growing medium.
- How many bags of topsoil equal a cubic yard?
- A standard 40 lb bag of topsoil is about 0.75 cubic feet. You need approximately 36 bags to equal one cubic yard (27 ft³). Bulk delivery is far more economical for any project over 1–2 cubic yards.