A soil calculator for topsoil, fill dirt and compost
Three materials, three jobs. Choose one under “Material”: the volume stays the same, and the weight and the bags follow.
- Topsoil. Screened soil for lawns and beds, and for levelling a yard or filling a shallow dip.
- Fill dirt. Subsoil with little organic matter, to raise a grade or fill a deep hole. It packs firm, and little grows in it: finish with topsoil.
- Compost. An amendment, not a soil. Spread it and mix it in; Oregon State University Extension says not to fill a bed with compost alone.
How deep should the soil be?
| For | Depth | In metric |
|---|---|---|
| Top-dressing a lawn | ¼ in | 0.6 cm |
| A new lawn | 4 in | 10 cm |
| A garden bed | 8 in | 20 cm |
Oregon State University Extension Service: On a lawn, spread compost one-quarter to one-half inch deep after core aeration. New vegetable beds: 3 to 4 in of compost, worked into the top 8 to 12 in. Existing beds: one-quarter to 1 in a year.
Iowa State University Extension and Outreach: Top-dress a lawn with a thin layer (1/4 in) of fine compost, together with core aeration.
Penn State Extension: A minimum of 4 to 6 in (settled depth) of good-quality topsoil is typically needed to establish good-quality turf.
A new lawn needs the most. Penn State Extension gives 4 to 6 in of good topsoil, measured after it has settled, as the minimum for good turf. Top-dressing an existing lawn is a thin layer, a quarter to half an inch, raked in after aerating.
Compost goes on thinner than soil. For a new vegetable bed the Oregon State guide gives 3 to 4 in, worked into the top 8 to 12 in; for an existing bed, a quarter inch to 1 in a year.
Worked example. A new lawn, 20 × 10 ft, with 4 in of topsoil.
- Area: 20 ft × 10 ft = 200 sq ft
- Volume: 200 sq ft × 4 in = 66.67 cu ft = 2.47 cubic yards
- Weight: 2.47 cubic yards × 1.1 tons = 2.72 tons
- In bags: 89 bags of 0.75 cu ft, or 67 bags of 1 cu ft
- In bulk: sold by the quarter yard, so order 2.5 cubic yards
Top-dressing a 1,000 sq ft lawn at 1/4 in takes far less: 20.83 cu ft, or 0.77 cubic yards.
Dirt calculator: how much does a yard weigh?
More than most pickups should carry. The calculator uses these figures, and takes your supplier’s in their place:
| Material | Tons per cubic yard | Typical range | Source |
|---|---|---|---|
| Topsoil | 1.1 (2,200 lb) | 1 to 1.3 | Sands & Soils, Topsoil.com |
| Fill dirt | 1.3 (2,600 lb) | 1 to 1.5 | Sands & Soils, Topsoil.com |
| Compost | 0.58 (1,150 lb) | 0.25 to 0.58 | Washington State University Extension, Sands & Soils |
Water is most of the difference. Topsoil.com puts a cubic yard of dry topsoil near 2,000 lb, moist topsoil at 2,200 to 2,600 lb and soaked topsoil up to 3,000 lb, and a half-ton pickup’s payload at about 1,500 to 2,200 lb. Read the payload on the sticker inside the driver’s door before you load a yard, or have it delivered.
Bags or bulk?
One cubic yard is 36 bags of 0.75 cu ft, 27 bags of 1 cu ft or 18 bags of 1.5 cu ft. The lawn above is 89 small bags: bulk is the easier way. Bags make sense for patching, for top-dressing a small lawn and where a truck cannot tip.
Soil settles after it is spread and watered. Where the finished level matters, as under sod, add 5 or 10% with the “extra” buttons.
Questions about topsoil and dirt
How many bags of topsoil make a yard?
36 bags of 0.75 cu ft, 27 bags of 1 cu ft or 18 bags of 1.5 cu ft. Bags sold by weight, such as 40 lb, are counted from the weight: the lawn in the example takes 136 of them.
How much does a yard of dirt weigh?
About 2,200 lb for topsoil and 2,600 lb for fill dirt, as suppliers quote them. Wet soil weighs more: up to 3,000 lb a yard when soaked.
How much fill dirt do I need?
Area times depth, as for topsoil: choose “Fill dirt” and enter the depth of the hole or the height to raise. The same 20 × 10 ft at 4 in is 2.47 cubic yards and 3.21 tons. For a deep fill, add extra: it compacts as it is placed.
How much topsoil for a new lawn?
Four to six inches, settled. One cubic yard covers 81 sq ft at 4 in deep, so a 1,000 sq ft lawn takes 12.35 cubic yards.
How much compost should I spread?
On a lawn, a quarter to half an inch after aerating: a cubic yard covers 1,296 sq ft at 1/4 in. A 1,000 sq ft lawn takes 0.77 cubic yards. On a new vegetable bed, 3 to 4 in, mixed into the soil.
Sources
- Sands & Soils, Topsoil. A cubic yard of topsoil weighs approximately 2,200 lb. Read on .
- Topsoil.com, Cubic Yard of Topsoil Weight. Dry topsoil 1,500 to 2,200 lb per cubic yard (about 2,000 on average), moist 2,200 to 2,600 lb, saturated 2,600 to 3,000 lb. Read on .
- Sands & Soils, Fill Dirt. A cubic yard of fill dirt weighs approximately 2,600 lb. Read on .
- Washington State University Extension, Recommended Compost Best Management Practices Guide (2016). To convert cubic yards of compost to tons, use 1,150 lb per cubic yard, or the bulk density on the compost’s own analysis. Read on .
- Sands & Soils, Leaf Compost. A cubic yard of leaf compost weighs approximately 500 to 600 lb. Read on .
- Oregon State University Extension Service, How to Use Compost in Gardens and Landscapes (EM 9308). On a lawn, spread compost one-quarter to one-half inch deep after core aeration. New vegetable beds: 3 to 4 in of compost, worked into the top 8 to 12 in. Existing beds: one-quarter to 1 in a year. Read on .
- Iowa State University Extension and Outreach, Core Aeration of Lawns. Top-dress a lawn with a thin layer (1/4 in) of fine compost, together with core aeration. Read on .
- Penn State Extension, Lawn Establishment. A minimum of 4 to 6 in (settled depth) of good-quality topsoil is typically needed to establish good-quality turf. Read on .
Updated . How we calculate. Found a mistake? Tell us.