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Soil Calculator – How Many Cubic Yards of Soil Do I Need? | SmartCalcBase
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Soil Calculator – Cubic Yards

Find out exactly how many cubic yards of soil, topsoil, or fill dirt you need for any garden, lawn, or landscaping project — instantly and for free.

Select your area shape
Tip: diameter = radius x 2
Soil you need
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How to use this soil calculator

  1. Select your area shape — rectangle for most garden beds and lawns, circle for round beds or trees, triangle for corner or diagonal areas.

  2. Enter the dimensions of your area and choose your unit. For irregular shapes, break the area into smaller rectangles, calculate each separately, and add the totals.

  3. Enter the depth — how deep you want to add soil. For lawn top-dressing, 1–2 inches is typical. For new garden beds, aim for 6–12 inches. For raised beds, enter the full height you want filled.

  4. Add a price per cubic yard (optional) to get an instant cost estimate. Topsoil typically costs $15–$75 per cubic yard depending on quality and your region.

  5. Click Calculate to get your result in cubic yards, cubic feet, approximate weight, and number of bags — ready to share with your supplier.

How do you calculate cubic yards of soil?

A cubic yard is a cube measuring 3 feet on each side — equal to 27 cubic feet. It’s the standard unit used by soil, mulch, and gravel suppliers in the US for bulk orders.

Cubic yards = (Length ft x Width ft x Depth ft) / 27

Tip: convert depth to feet first — divide inches by 12, or cm by 30.48

For circular areas, the formula is (pi x radius^2 x depth in ft) / 27. For triangles it’s (0.5 x base x height x depth in ft) / 27. This calculator handles all three shapes automatically.

Always order 10–15% more than your exact calculation to account for settling, compaction, and minor measurement errors. Most suppliers round up to the nearest quarter-yard anyway.

How deep should you add soil?

1–2 inLawn top-dressing or overseeding
3–4 inFlower beds and ground cover
6–8 inVegetable gardens and shrubs
12+ inRaised beds and deep-root crops

How many cubic yards of soil for common area sizes?

Area (sq ft)2 in deep4 in deep6 in deep12 in deep
50 sq ft0.31 yd³0.62 yd³0.93 yd³1.85 yd³
100 sq ft0.62 yd³1.23 yd³1.85 yd³3.70 yd³
200 sq ft1.23 yd³2.47 yd³3.70 yd³7.41 yd³
500 sq ft3.09 yd³6.17 yd³9.26 yd³18.52 yd³
1,000 sq ft6.17 yd³12.35 yd³18.52 yd³37.04 yd³
2,000 sq ft12.35 yd³24.69 yd³37.04 yd³74.07 yd³

Values assume rectangular areas. Use the calculator above for circles, triangles, or irregular shapes.

Topsoil, fill dirt, or garden soil — which do you need?

TypeBest forAvg. cost / yd³Notes
TopsoilLawn repair, leveling, landscaping$15 – $45Top layer of earth; variable quality
Garden soilVegetable beds, flower beds$35 – $75Blended with compost; ready to plant
Fill dirtGrading, filling holes, raising grade$5 – $25No organic matter; not for plant beds
Potting mixContainers, raised beds$40 – $90Lightweight; excellent drainage
CompostSoil amendment, top-dressing$25 – $60Mix at 20–30% by volume for best results

Frequently asked questions about soil calculations

A standard 4×8 raised bed that is 12 inches deep needs approximately 1.19 cubic yards of soil (4 x 8 x 1 ft / 27 = 1.19 cu yd). For a 6-inch deep bed, you need about 0.59 cubic yards. Most suppliers sell a minimum of 0.5 yards, so one half-yard delivery typically covers a single raised bed.
A cubic yard of topsoil weighs between 1,000 and 1,300 lbs — roughly half a ton — depending on moisture and composition. Garden soil blended with compost tends to be lighter (~800–1,000 lbs), while wet clay-heavy soil can exceed 1,500 lbs per cubic yard. A standard pickup truck can safely carry about 0.5–1 cubic yard.
One cubic yard equals 27 cubic feet. A standard 1 cu ft bag fills exactly 1/27 of a cubic yard, so you need 27 bags. Many bags at garden centers are 0.75 or 0.5 cu ft — in those cases you’d need 36 or 54 bags. For large projects, bulk delivery is almost always cheaper than bagged soil.
Break the area into smaller rectangles, circles, or triangles. Calculate each shape separately using this calculator and add the results. For very irregular shapes, measure the widest length and widest width, calculate as a rectangle, then reduce by 10–20% for areas clearly not fully filled.
For establishing a new lawn from seed or sod, 4–6 inches of topsoil is ideal — that’s where most grass roots live. For top-dressing an existing lawn to fill low spots, 1–2 inches is enough. Any more and you risk smothering the existing grass.
Yes — always add 10–15% to your calculated total. Soil settles and compacts after watering, so the final settled depth will be less than what you spread. Minor measurement errors and spillage add up too. It’s much easier to have a small leftover pile than to place a second delivery order.
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