Topsoil Calculator
Work out how much topsoil you need in cubic yards, bags and tons for a new lawn, garden bed or leveling job, with extra for settling.
Results
| Item | Value |
|---|
Quick Answer
Topsoil in cubic yards = length × width (ft) × depth (in) ÷ 12 ÷ 27. A 30 ft by 20 ft lawn at 4 inches settled depth, plus 15% for settling, needs about 8.52 cubic yards, or about 307 bags of 0.75 cubic feet.
Embed this calculator
Adjust the size if needed, then copy the code below into your page or blog. The calculator will load in an iframe and stay updated automatically.
Table of Contents
- Topsoil Calculator
- Quick Answer
- Related Calculators
- How This Topsoil Calculator Works
- How to Use the Topsoil Calculator
- Core Formulas
- Key Terms
- Worked Example
- Real-Life Examples
- Topsoil vs Garden Soil vs Compost
- How Deep Should Topsoil Be?
- Common Mistakes to Avoid
- Frequently Asked Questions
- References & Sources
How This Topsoil Calculator Works
Enter the length and width of the area, and the depth of soil you want after it settles. The calculator finds the volume, adds extra for settling, and shows the amount in cubic yards, cubic feet, bags and tons. Add prices to compare bags with bulk delivery.
Quick explanation: topsoil is sold by the bag in cubic feet, or in bulk by the cubic yard or ton.
- 1 cubic yard: 27 cubic feet.
- Settling: loose soil sinks as it firms up, so order a little extra.
- Weight: varies with moisture, so check with your supplier.
How to Use the Topsoil Calculator
- Measure the length and width of the area in feet.
- Enter the settled depth you want, such as 4 to 6 inches for a new lawn.
- Keep the settling allowance at about 10% to 20%, or change it.
- Enter your bag size and your supplier’s weight per cubic yard.
- Press Calculate and compare bags, bulk and tons.
Core Formulas
- Area: length × width
- Cubic feet: area × depth in inches ÷ 12 × (1 + settling %)
- Cubic yards: cubic feet ÷ 27
- Bags: cubic feet ÷ bag size, rounded up
- Tons: cubic yards × weight per cubic yard
Key Terms
- Topsoil: the upper layer of soil, usually richer in organic matter.
- Cubic yard: a volume 3 ft × 3 ft × 3 ft, or 27 cubic feet.
- Settled depth: the depth after soil has firmed and settled.
- Top dressing: a thin layer of soil or compost spread over a lawn.
- Subsoil: the firmer soil layer below the topsoil.
Worked Example
You are filling a raised bed 8 ft by 4 ft to 10 inches deep, using 1 cubic foot bags, with 15% extra for settling.
- Area = 8 × 4 = 32 sq ft
- Cubic feet = 32 × 10 ÷ 12 × 1.15 = 30.7 cu ft
- That is 1.14 cubic yards, or 31 bags
Real-Life Examples
- New lawn: a 30 ft by 20 ft yard at 4 inches settled needs about 8.52 cubic yards, which is usually cheaper in bulk than 307 bags.
- Raised bed: an 8 ft by 4 ft bed, 10 inches deep, needs about 31 one-cubic-foot bags.
- Top dressing: 1,000 sq ft at 1/4 inch needs about 0.77 cubic yards.
- Ordering by the ton: at 1.1 tons per cubic yard, 8.52 cubic yards is about 9.4 tons.
Topsoil vs Garden Soil vs Compost
- Topsoil: general soil for filling, leveling and lawns.
- Garden soil: topsoil blended with organic matter for beds.
- Compost: decayed organic matter, mixed into soil to improve it rather than used alone.
- Mulch: a top layer to hold moisture and stop weeds. Try our Mulch Calculator.
How Deep Should Topsoil Be?
Lawn depth from Penn State Extension. Other depths are common guidelines; your soil and plants may need more.
| Project | Settled depth |
|---|---|
| New lawn from seed or sod | 4 to 6 inches (Penn State Extension) |
| Top dressing an existing lawn | About 1/4 to 1/2 inch |
| Flower beds | 6 to 8 inches |
| Vegetable raised beds | 8 to 12 inches |
| Filling low spots | The depth of the hole |
Common Mistakes to Avoid
- Forgetting settling. Loose soil sinks, so order more than the finished depth.
- Mixing up inches and feet. Enter depth in inches and length and width in feet.
- Spreading too thin for a lawn. New lawns need several inches for strong roots.
- Burying trees. Do not pile soil against tree trunks.
- Skipping a soil test. Test pH and nutrients before planting.
Frequently Asked Questions
Penn State Extension says a minimum of 4 to 6 inches of settled topsoil is typically needed for good turf.
36 bags of 0.75 cubic feet, or 27 bags of 1 cubic foot.
It varies a lot with moisture, compaction and soil type, so ask your supplier. Wet soil weighs much more than dry soil. Enter their figure in the calculator to convert cubic yards to tons.
About 81 sq ft at 4 inches deep, or 162 sq ft at 2 inches deep.
Bags suit small jobs. For more than a cubic yard or two, bulk delivery is usually cheaper.
Many people add 10% to 20% for settling and uneven ground.
A thin top dressing is fine. Thick layers will smother the grass.
Fill dirt is mostly subsoil with little organic matter, used for raising grade. Topsoil is for growing plants.
Find the area with 3.14 × radius², then enter the area as length with a width of 1.
Loosening the ground below helps the layers blend and improves drainage.
Many vegetables grow well in 8 to 12 inches of soil.
No. Potting mix is a light blend for containers and is not meant for lawns or beds.
References & Sources
| Source | Used For | Link |
|---|---|---|
| Penn State Extension, Lawn Establishment | Topsoil depth for new lawns. | https://extension.psu.edu/lawn-establishment |
| Iowa State University Extension, Seeding a New Lawn | Preparing soil for a new lawn. | https://yardandgarden.extension.iastate.edu/how-to/seeding-new-lawn |