Soil Calculator — Cubic Feet
Calculate topsoil, garden soil and compost in real time. Bag counts update with every keystroke.
Topsoil vs Garden Soil vs Compost
Topsoil is general-purpose surface soil — used for leveling, lawn underlayment and shallow planting. It's the cheapest option per cubic foot and typically sold in bulk.
Garden soil is topsoil amended with compost, peat and nutrients. It costs more per cubic foot but performs better in beds and containers.
Compost is decomposed organic matter, applied as an amendment (1–2 inches) on top of existing soil or mixed with topsoil at 30–50% for raised beds.
How Deep Should Soil Be?
| Application | Recommended Depth |
|---|---|
| Lawn topsoil | 2–4 inches |
| Annual flower bed | 6–8 inches |
| Vegetable garden | 8–12 inches |
| Raised bed | 10–18 inches (full) |
| Tree planting hole | 2× root ball depth |
| Sod underlayment | 2–3 inches |
Bag Size Reference
Bagged soil typically comes in 0.5, 1, 1.5 and 2 cubic foot bags. To convert cubic feet to bags, divide your total by the bag size.
For volumes over 1 cubic yard (27 ft³), bulk delivery is almost always cheaper.
Cost Estimation Tips
Bulk topsoil ranges from $15–$50 per cubic yard delivered (varies by region). Bagged topsoil runs $3–$5 per cubic foot. For a 4×8×1 ft raised bed (32 ft³), bagged would cost ~$130; bulk delivery would be ~$30–$60 plus a delivery fee.
Always order 5–10% extra to account for settling and irregular bed shapes.
Finishing the Bed: Mulch and Weight
Most planting beds need a mulch layer on top of the soil once planting is done — see the mulch calculator to figure out that quantity separately, since mulch depth (2–4 in) is much shallower than soil depth. Before ordering bulk soil, it's also worth checking total weight: wet topsoil runs close to 100 lb per cubic foot, so a 1 cubic yard delivery (27 ft³) weighs around 2,700 lbs — use the weight calculator to confirm your driveway, deck or truck can handle a delivered pile that heavy.
Frequently Asked Questions
How much soil do I need for a 4x8 raised bed?
At 12 inches deep, you need 32 cubic feet (4 × 8 × 1). That's 32 bags of 1 ft³ soil or about 1.2 cubic yards.
How deep should topsoil be for a new lawn?
Spread topsoil 2–4 inches deep over the existing grade. 3 inches (0.25 ft) is typical.
How many bags of soil in a cubic yard?
27 bags of 1 ft³, 54 bags of 0.5 ft³, or 13.5 bags of 2 ft³.
What's the difference between topsoil and garden soil?
Topsoil is general-purpose, often used for grading and lawns. Garden soil is enriched with compost and nutrients for planting.
How heavy is a cubic foot of topsoil?
About 70–80 pounds per cubic foot dry; up to 100 lb/ft³ when wet.
How much soil for a tree planting hole?
Treat as a cylinder: π × r² × depth. A 3 ft wide × 2 ft deep hole = 14.1 ft³.
Is bulk soil cheaper than bagged?
Bulk (sold by cubic yard) is typically 40–60% cheaper per cubic foot than bagged, but requires a truck or trailer.
How do I calculate soil for an L-shaped bed?
Divide into rectangles, calculate each separately, then add the totals.