How Do You Calculate How Much Soil You Need?
Soil volume equals area times depth. Multiply length by width in feet, multiply by the depth in inches, divide by 12 for cubic feet, then divide by 27 for cubic yards. Divide cubic feet by the bag size for the number of bags.
The formula is length (ft) × width (ft) × depth (in) ÷ 12 = cubic feet. A 20 × 15 ft garden area at 4 inches holds 300 × 4 ÷ 12 = 100 cubic feet, which is 100 ÷ 27 = 3.7 cubic yards. Circular areas use π × radius² for the area: an 8 ft circle covers 50.3 sq ft and takes 25.1 cubic feet of soil at 6 inches. In metric, multiply length × width in meters by the depth in centimeters and divide by 100 for cubic meters; one cubic meter equals 1,000 liters.
Irregular areas are easiest to split into rectangles and circles, calculate separately and add together. For a sloped fill, measure the depth at several points and use the average. The soil calculator sits alongside the other free garden planning calculators and tools that turn bed dimensions into material quantities.
How Deep Should Topsoil Be?
Topsoil depth depends on the job: 4 to 6 inches (10–15 cm) for a new lawn, 8 to 12 inches (20–30 cm) for vegetable and flower beds, and no more than about ½ inch per application when top-dressing an existing lawn.
Grass roots grow mostly in the top 4 to 6 inches of soil, so a new lawn seeded or sodded over less than 4 inches of topsoil dries out quickly in summer. Vegetables and perennials root deeper and establish best in 8 to 12 inches of loose, fertile soil. Leveling low spots in an established lawn works in thin layers: spread up to ½ inch, let the grass grow through, and repeat, because a thick layer smothers the turf.
Beds built above ground level are measured differently, since a frame sets the height and the fill is usually a blend rather than straight topsoil. The raised bed soil calculator with topsoil and compost mix ratios handles multiple beds and splits the total into each mix ingredient.
How Much Area Does a Cubic Yard of Soil Cover?
One cubic yard of soil covers 324 square feet at 1 inch deep, 108 square feet at 3 inches, 81 square feet at 4 inches and 54 square feet at 6 inches. Coverage equals 324 divided by the depth in inches.
| Soil depth | Coverage per cubic yard | Coverage per cubic meter |
|---|---|---|
| 1 in (3 cm) | 324 sq ft | 39.4 m² |
| 2 in (5 cm) | 162 sq ft | 19.7 m² |
| 3 in (8 cm) | 108 sq ft | 13.1 m² |
| 4 in (10 cm) | 81 sq ft | 9.8 m² |
| 6 in (15 cm) | 54 sq ft | 6.6 m² |
| 8 in (20 cm) | 40.5 sq ft | 4.9 m² |
| 12 in (30 cm) | 27 sq ft | 3.3 m² |
Coverage = 324 sq ft ÷ depth in inches per cubic yard; 100 m² ÷ depth in centimeters per cubic meter.
How Much Does a Cubic Yard of Topsoil Weigh?
A cubic yard of topsoil typically weighs about 1.0 to 1.3 tons, or roughly 2,000 to 2,600 pounds. In metric, a cubic meter weighs about 1.2 to 1.5 tonnes. Moisture, clay content and organic matter shift the weight.
Weight matters more than volume for hauling. Rain-soaked soil can weigh noticeably more than the same volume of dry soil, and heavy clay weighs more than sandy loam. A typical half-ton pickup truck reaches its payload limit with only about half to three-quarters of a cubic yard of topsoil, so check the truck's rated payload before loading bulk soil. The weight shown by the calculator is an approximation based on this typical range, not a supplier's scale weight.
How Many Bags of Soil Are in a Cubic Yard?
A cubic yard holds 27 cubic feet of soil, which equals 36 bags of 0.75 cubic feet, 27 bags of 1 cubic foot, 18 bags of 1.5 cubic feet or 13.5 bags of 2 cubic feet. Round bag counts up.
| Bag size | Bags per cubic yard | Bags to buy |
|---|---|---|
| 0.75 cu ft (21 L) | 36 | 36 |
| 1 cu ft (28 L) | 27 | 27 |
| 1.5 cu ft (42 L) | 18 | 18 |
| 2 cu ft (57 L) | 13.5 | 14 |
Bags per cubic yard = 27 ÷ bag size in cubic feet, rounded up to whole bags.
Bags suit small beds and projects under about 1 cubic yard, where a few dozen bags are easy to carry and spread. Bulk soil, sold by the cubic yard and delivered by truck, usually costs less per yard for lawns and large fills. The same 27-cubic-feet-per-yard conversion applies to bark and wood chips, and the mulch calculator for cubic yards and bags of mulch sizes the finishing layer that goes on top of new beds.
Should You Use Topsoil, Garden Soil or Potting Soil?
Topsoil suits lawns, grading and filling low areas. Garden soil — topsoil blended with compost — suits in-ground vegetable and flower beds. Potting soil, a soilless mix of peat or coir, bark and perlite, is made for containers and houseplants.
Screened topsoil is the cheapest per yard and is meant to be mixed with the existing ground or improved with compost. Bagged garden soil already contains organic matter and can be dug into beds as delivered. Potting soil stays light and drains freely in a pot, where real soil compacts and waterlogs roots; the potting soil calculator for pots and containers sizes mix by pot diameter instead of area. Soil preferences differ between species, and the plant care guides for more than 800 species describe the soil, watering and light each plant needs.
Frequently Asked Questions
- How many square feet does a yard of topsoil cover?
- One cubic yard of topsoil covers 324 square feet at 1 inch deep, 81 square feet at 4 inches and 54 square feet at 6 inches. Divide 324 by the depth in inches to get the coverage for any depth.
- How much does a cubic yard of topsoil weigh?
- A cubic yard of topsoil typically weighs about 1.0 to 1.3 tons (2,000 to 2,600 pounds). Wet soil and soil with a high clay content weigh more; sandy or compost-rich soil weighs less.
- How many bags of topsoil make a yard?
- One cubic yard equals 27 cubic feet: 36 bags of 0.75 cubic feet, 27 bags of 1 cubic foot, 18 bags of 1.5 cubic feet or 13.5 bags of 2 cubic feet.
- How much topsoil do I need for a new lawn?
- A new lawn needs 4 to 6 inches of topsoil. A 1,000 square foot lawn at 4 inches takes 333 cubic feet, or 12.3 cubic yards; at 6 inches it takes 500 cubic feet, or 18.5 cubic yards.
- Should I order extra soil?
- Order about 10% more soil than the calculated volume. Loose soil compacts as it is spread, raked and watered, and low spots in the ground usually take more fill than the average depth suggests.