Topsoil & Fill Dirt Volume
Last reviewed: April 2026
Calculate how much topsoil, garden soil, or fill dirt you need in cubic yards, cubic feet, and bags. Enter bed dimensions and desired depth. This calculator runs entirely in your browser — your data stays private, and no account is required.
Soil volume is calculated as length × width × depth, converted to cubic yards (the standard unit for bulk soil purchasing). One cubic yard equals 27 cubic feet and covers approximately 108 square feet at 3 inches deep or 54 square feet at 6 inches deep.[1] Raised bed gardens need the most soil per square foot — a standard 4×8 foot raised bed that is 12 inches tall requires about 1.2 cubic yards (roughly 1.5 tons) of soil mix. Bulk delivery is far cheaper than bagged soil for quantities over 1 cubic yard: bulk runs $30-$60 per cubic yard versus $4-$8 per 1 cubic foot bag ($108-$216 per cubic yard equivalent).[2] For raised beds, a mix of 60% topsoil, 30% compost, and 10% aeration material (perlite or coarse sand) provides good drainage and fertility. Pre-mixed raised bed soil is available but costs 50-100% more than mixing your own from bulk components.[3] Use the Mulch Calculator for top-dressing material estimates.
Topsoil is the uppermost layer of natural soil, suitable for general landscaping. Garden soil is topsoil blended with compost and amendments for planting. Potting soil (soilless mix) uses peat, perlite, and vermiculite for containers — it is lighter and drains better but should not be used in ground beds. For vegetable gardens, the ideal mix is roughly 60% topsoil, 30% compost, and 10% perlite or coarse sand for drainage. Test your existing soil pH before amending — most vegetables prefer pH 6.0–7.0. Lime raises pH (acidic soil), sulfur lowers it (alkaline soil). Calculate amendments with our Soil Amendment Calculator and total volume with our Cubic Yards Calculator.
| Bed Size | Depth 4" | Depth 6" | Depth 12" |
|---|---|---|---|
| 4×4 ft | 0.2 cu yd | 0.3 cu yd | 0.6 cu yd |
| 4×8 ft | 0.4 cu yd | 0.6 cu yd | 1.2 cu yd |
| 4×12 ft | 0.6 cu yd | 0.9 cu yd | 1.8 cu yd |
| 10×10 ft | 1.2 cu yd | 1.9 cu yd | 3.7 cu yd |
Calculating the right amount of soil for garden beds, raised planters, fill projects, and lawn establishment prevents the frustration of either running short mid-project or paying for excess material you do not need. Soil is typically sold by the cubic yard — one cubic yard covers 324 square feet at 1 inch deep, 162 square feet at 2 inches, 108 square feet at 3 inches, or 81 square feet at 4 inches. Understanding these ratios helps you quickly estimate needs for any project.
Topsoil: The uppermost 2–8 inches of native soil, screened to remove rocks and debris. Quality varies enormously — premium screened topsoil contains organic matter and supports plant growth, while cheap fill topsoil may be subsoil relabeled. Best for grading, lawn establishment, and general fill. Typical cost: $20–$50 per cubic yard delivered. Garden soil/planting mix: A blend of topsoil, compost, and amendments (perlite, vermiculite, peat moss) formulated for planting beds. Higher organic content than straight topsoil, better water retention, and improved nutrient availability. Cost: $35–$65 per cubic yard. Compost: Fully decomposed organic matter — the gold standard soil amendment. Improves soil structure, water retention, drainage, nutrient content, and beneficial microbial activity in any soil type. Apply 2–4 inches annually to garden beds. Cost: $25–$50 per cubic yard ($3–$7 per bag). Fill dirt: Subsoil with no organic content, used for grading, filling holes, and establishing base layers. Not suitable for planting. Cheapest option at $5–$15 per cubic yard, sometimes free from construction sites.
Raised beds require surprisingly large soil volumes. A standard 4×8 foot bed, 12 inches deep needs 1.2 cubic yards — roughly 1.5 tons of material. The ideal raised bed fill combines 60% topsoil, 30% compost, and 10% aeration material (perlite, coarse sand, or pumice). For beds deeper than 12 inches, you can fill the bottom third with a cheaper base layer (logs, wood chips, straw in a technique called Hügelkultur, or plain fill dirt) and use quality planting mix only in the top 8–12 inches where roots concentrate. This approach reduces costs by 30–40% on deep beds while providing adequate root zone nutrition and improved long-term drainage.
Before buying new soil, test what you have. Soil testing through your county cooperative extension service ($10–$30) reveals pH, nutrient levels, organic matter content, and texture composition — enabling targeted amendments instead of guesswork. Clay soil benefits from adding gypsum (to improve structure without changing pH), coarse organic matter, and expanded shale. Sandy soil benefits from heavy organic matter additions (3–4 inches of compost annually) to improve water and nutrient retention. Acidic soil (pH below 6.0) is corrected with agricultural lime; alkaline soil (pH above 7.5) is corrected with eleite sulfur or acidic amendments like peat moss.
Bulk soil delivery (dump truck or trailer) is dramatically cheaper than bagged soil for projects requiring more than 2–3 cubic yards. One cubic yard of soil weighs approximately 1.5–2 tons depending on moisture content. Ensure your delivery access point can handle the truck weight and that you have a suitable dumping area within wheelbarrow distance of your project. For lawn-scale topsoil spreading, a tow-behind spreader or Harley rake (rental: $150–$300/day) saves days of manual labor compared to shoveling and raking. Budget for 4–6 inches of quality topsoil for new lawn establishment over poor native soil, or 2–3 inches for overseeding existing thin lawns.
| Project | Typical Depth | Volume per 100 sq ft |
|---|---|---|
| Lawn topdressing | 0.25–0.5 in | 0.08–0.15 cu yd |
| Garden bed amendment | 2–4 in | 0.6–1.2 cu yd |
| New lawn topsoil | 4–6 in | 1.2–1.9 cu yd |
| Raised bed fill | 8–12 in | 2.5–3.7 cu yd |
Fresh soil settles by 10–20% after watering and natural compaction. Order 10–15% extra material to account for this settling — otherwise you will end up with beds and grades lower than planned. For projects where compaction is critical (under pavers, foundations, or structural fill), soil must be mechanically compacted in 6-inch lifts using a plate compactor or jumping jack tamper, with each layer moistened before compacting. Garden beds should never be mechanically compacted because compressed soil inhibits root growth, reduces water infiltration, and decreases microbial activity.
The best time for soil work depends on your project. For new garden beds, fall preparation is ideal — amendments added in fall have all winter to integrate with existing soil biology. For lawn establishment, early fall (September–October in northern climates) or early spring (March–April) provides the temperature and moisture conditions grass seed needs. Avoid working wet soil — digging, tilling, or driving equipment on saturated soil destroys structure and creates compaction that persists for years. Test by squeezing a handful: if it forms a tight ball that does not crumble when poked, it is too wet to work. Wait for it to dry to the point where it crumbles freely before starting your landscaping project.
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See also: Soil Amendment Calculator · Mulch Calculator · Cubic Yards Calculator