Soil Calculator

For a 4x8 foot raised bed that's 12 inches deep, you need 1.2 cubic yards (32 cubic feet) of soil. This equals approximately 24 bags of 1.5 cubic foot bagged soil ($96-192), or bulk delivery is more economical ($48-90 including delivery for that quantity). For deeper beds: 18" depth = 1.8 yards, 24" depth = 2.4 yards.

Topsoil is the top 4-12" layer of soil that contains organic matter, nutrients, and beneficial microorganisms—essential for plant growth. Fill dirt is subsoil excavated from below the topsoil layer. It's mostly clay, sand, and rock with NO organic matter or nutrients. Fill dirt is used for structural purposes like leveling, filling holes, and building up terrain. Never use fill dirt for planting gardens—plants will fail to grow.

One cubic yard equals 27 cubic feet. Standard 1.5 cubic foot bags require 18 bags per cubic yard. Larger 2 cubic foot bags need 13.5 bags per cubic yard. At $4-8 per 1.5 cu ft bag, bagged soil costs $72-144 per yard vs $20-50 for bulk topsoil delivered. Bulk delivery becomes cost-effective at about 1.5 cubic yards (27 bags).

Minimum 6 inches for lettuce, herbs, and shallow-rooted annuals. 10-12 inches is ideal for tomatoes, peppers, and most vegetables—this is the professional standard. 18+ inches for root vegetables like carrots, parsnips, and potatoes. Deeper soil provides better drainage, moisture retention, and healthier root systems. For new lawns, 6-8 inches of quality topsoil is recommended.

Buy bagged soil for small projects under 1 cubic yard (27 cubic feet). For projects needing 1.5+ cubic yards, bulk delivery costs 50-70% less. Example: 10 cubic yards bulk = $200-500 delivered. Same amount bagged = $720-1,440 + hauling costs. A 4x8x12" raised bed (1.2 yards) is near the break-even point. For multiple beds or large gardens, always choose bulk.

Topsoil weighs approximately 2,000 lbs (1 ton) per cubic yard when moderately moist. Fill dirt is denser at 2,200 lbs per yard. Compost is lighter at 1,000 lbs per yard. Garden mix (topsoil/compost blend) weighs about 1,500 lbs per yard. Weight varies ±10-20% based on moisture content. Wet soil can weigh 20-30% more than dry soil.

No! Fill dirt contains no organic matter or nutrients and is unsuitable for planting. Plants grown in fill dirt alone will be stunted, yellow, and may die. However, you CAN use fill dirt as the bottom layer (lower 50-70% of depth) for raised beds or to build up low areas, then cap with 4-6 inches of quality topsoil or garden mix for planting. This method saves 30-50% on soil costs for deep beds.

For irregular shapes, divide the area into rectangles, triangles, or circles, calculate each section separately, then add them together. Circle formula: 3.14 × (radius)² × depth / 27 = cubic yards. Triangle: (base × height / 2) × depth / 27 = cubic yards. For very irregular beds, estimate the average length and width. Always order 10-15% extra to account for settling and measurement variations.

Delivery times vary by season and supplier. Spring (March-May) is peak season—expect 1-3 week waits. Summer and fall (June-October) typically offer 3-7 day delivery. Winter (November-February) often has same-week or next-day delivery. Always call 2-3 suppliers for availability and pricing. Some suppliers offer scheduled delivery dates, while others deliver within a time window (e.g., "Tuesday morning").

The ideal raised bed mix is 50% quality topsoil + 50% aged compost. This provides excellent nutrition, drainage, and structure. Alternative: 40% topsoil + 30% compost + 20% peat moss + 10% perlite for the ultimate growing medium. Budget option: 60% screened topsoil + 40% compost works well. Avoid 100% compost (too rich, poor structure) or 100% topsoil (benefits from added organic matter).

It depends on quality. Premium topsoil (3-5% organic matter) can be used as-is. Screened topsoil (1-3% organic matter) benefits from adding 2-3 inches of compost mixed in. Native or unscreened topsoil should have 30-40% compost added. For raised beds, ALWAYS mix in compost for best results. For lawns, quality screened topsoil is fine without amendments. Test soil pH before planting—adjust with lime (raise pH) or sulfur (lower pH) if needed.

Order 10-15% extra for fill dirt (minimal settling). Order 15-20% extra for topsoil (moderate settling). Order 20-25% extra for compost and garden mix (highest settling). Example: Need 10 yards of topsoil? Order 11.5-12 yards to account for settling. Soil settles most in the first 2-4 weeks, especially after watering and rain. It's better to have extra soil on-site than to pay for a second delivery ($50-150 delivery fee).