Calculate how much soil you will need for your landscaping project
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Soil Needed:
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Cubic Yards
pH Adjustment Tips
Conduct a soil pH test to determine the specific amendment needs for your project.
When using this calculator, each input helps calculate an accurate estimate for your project.
How to use this calculator?
When using this calculator, each input helps calculate an accurate estimate for your project.
Soil is composed of minerals, organic matter, water, and air.
The common soil types are:
Soil volume is a critical factor in successful gardening and landscaping. The amount of soil available to plants directly impacts their health, growth potential, and long-term survival. According to USDA NRCS soil health guidance, adequate soil volume and structure are foundational to healthy plant development.
Soil volume is important for the following reasons:
The quality of your soil mix directly impacts your gardening or landscaping needs. Consider the following options:
Amendments are materials added to soil to improve its physical, chemical, or biological properties. These materials modify soil structure, alter pH levels, provide essential nutrients, or enhance beneficial microorganism activity.
Soil Amendments are important for the following reasons:
The following table provides a helpful reference for choosing soil amendments based on each soil type:
| Soil | Recommended Amendment |
|---|---|
| Heavy clay soil | Compost, sand, gypsum |
| Sandy soil | Compost, coconut coir |
| Acidic soil (low pH) | Lime, wood ash |
| Alkaline soil (high pH) | Sulfur, peat moss |
Soil volume is calculated in cubic units, a three-dimensional measurement: Volume = Length x Width x Depth. Understanding the difference between cubic feet, cubic yards, and the bag sizes you find at a garden center will help you buy the right amount without overspending or running short. University extension programs such as University of Minnesota Extension and Penn State Extension provide guidance on soil volume planning for raised beds and garden areas.
| Unit | Definition | Common Use |
|---|---|---|
| Cubic foot (cu ft) | A 1 ft × 1 ft × 1 ft block of space | Bag sizing: most bags are 1, 1.5, or 2 cu ft |
| Cubic yard (cu yd) | 27 cubic feet (3 ft × 3 ft × 3 ft) | Bulk soil orders and landscape supply deliveries |
| Cubic meter (m³) | 35.3 cubic feet | Metric projects and international suppliers |
Soil settles after installation, especially when it is freshly added and loosely poured. Typical settling ranges from 10–20% depending on soil type and moisture conditions. Sandy mixes compact less. Organic-rich mixes and compost-heavy blends can settle considerably over the first few months of watering.
Practical implications:
Finished your soil estimate? Consider adding a mulch layer on top to retain moisture and suppress weeds. See our Mulch Calculator for coverage estimates.
This calculator is based on standard volume formulas for rectangular, circular, and triangular areas, with conversions between cubic inches, cubic feet, and cubic yards. The Homebase Calculators Editorial Team reviews formulas, input definitions, and explanatory content for consistency and clarity. Volume estimates assume consistent depth and do not account for soil compaction or settling after filling. The sources below are provided for educational grounding and deeper reading on soil volume planning, raised bed construction, and garden soil selection.
These resources can help you choose the right soil mix, plan your raised bed layout, and prepare your garden space for planting.
This calculator is for estimation purposes only. Results may vary based on soil type, settling, and site conditions.
Verify your bed dimensions, desired fill depth, and soil type with your supplier or nursery before ordering. Coverage per bag or per cubic yard depends on the specific product and will settle after filling.
For regional guidance on soil selection and raised bed preparation, consult your local university cooperative extension service, which provides evidence-based gardening guidance specific to your climate and soil type.
Multiply the length × width × depth of the raised bed to get cubic feet. Then divide by 27 to convert to cubic yards, or divide by the bag size (e.g., 1.5 cu ft) to determine bags needed. For example: a 4 ft × 8 ft × 1 ft bed = 32 cubic feet = 1.19 cubic yards. Always buy 10–15% extra to account for settling.
Topsoil is the uppermost natural layer of earth: relatively unmodified, used for filling and grading, and not specifically formulated for planting. Garden soil is a blend of topsoil and composted organic material, and is intended for planting beds. Potting mix is specifically formulated for containers; it is lightweight, drains well, and should not be used for in-ground beds or lawn work. For raised beds, a pre-blended "raised bed mix" (often a mix of topsoil, compost, and perlite) is ideal.
Most vegetables need at least 6–12 inches of loose, well-draining soil for adequate root development. Shallow-rooted crops like lettuce and herbs can thrive in 6 inches. Deep-rooted plants like carrots, tomatoes, and squash benefit from 12 inches or more. The USDA National Resources Conservation Service recommends 8–12 inches as a general guideline for productive kitchen garden beds. See USDA NRCS Soil Health Resources.
Yes, and it is often recommended. Simply layering new soil on top without mixing can create stratification, an invisible barrier between soil layers that restricts water movement and root growth. Till or loosen the top 4–6 inches of existing soil and blend new material in before more deeply filling. For lawns and patches, topdressing with a thin 1–2 inch layer can be done without tilling.
Typical soil settling ranges from 10–20% of the applied depth over the first few months of watering and decomposition. Compost-heavy mixes settle more than sandy mixes. Plan for settling by overfilling beds slightly above your target grade. In lawns, expect 10–15% settling and apply seed once the first layer has settled, topdressing again if needed after the first growing season.
One cubic yard equals 27 cubic feet. Bagged soil is typically sold by the cubic foot (1, 1.5, or 2 cu ft per bag). Bulk soil is sold by the cubic yard. If your project requires 3 cubic yards, that is 81 cubic feet, or approximately 54 bags of 1.5 cu ft each. Bulk orders almost always cost less per cubic yard than bagged, especially above 2 cubic yards.
For filling containers or raised beds where you are starting fresh, a soil test is usually not necessary. However, for in-ground garden beds or lawn improvement where you are amending existing soil, a basic pH and nutrient test is very helpful. Most university extension services and many garden centers offer soil testing kits or mail-in testing for $15–$30. The results tell you what amendments to add and in what quantities. State cooperative extension offices often offer low-cost or free soil testing; check with your local land-grant university's extension service.
Break the irregular shape into multiple simpler shapes (rectangles, triangles, or circles), calculate the area of each, and add the totals. For very complex shapes, use the grid counting method: overlay a measured grid and count the squares that fall mostly within your area. Enter the total square footage into this calculator's "Irregular" shape option. Always add a 10–15% buffer to your result for irregular shapes to account for measurement error.
Found a calculation error, an outdated assumption, or something unclear on this page? Contact the Homebase Calculators Editorial Team to let us know. We review submissions and update pages when corrections are warranted.