Formula
Settle and waste both multiply the measured volume. They stack: 5% waste and 10% settle is 1.05 × 1.10 = 1.155 times the measured yards. Bags then round up.
order = measured × (1 + waste ÷ 100) × (1 + settle ÷ 100)
yards = cubic feet ÷ 27
bags = ceil(order cubic feet ÷ bag size)
tons = order yards × tons per yard
Bag sizes are 0.75, 1.0, and 1.5 cubic feet, the three fills commonly printed on garden-soil bags. Screened topsoil is 1.10 ton/yd³. That number was not taken from one extension bulletin. Wet soil is heavier, and the page does not guess moisture.
Worked examples
10 × 20 ft × 4 in, 5% waste, 10% settle. Measured volume is 66.67 ft³, 2.47 yd³. The order is 2.47 × 1.05 × 1.10 = 2.85 yd³. At 1.5 cu ft per bag that is 52 bags. At 1.10 ton/yd³ the order weighs 3.14 tons.
A 4 ft circle, 6 in deep, no allowances. π × 4 × 0.5 = 6.28 ft³, 0.23 yd³.
A triangle 6 × 8 ft, 3 in deep. 6 ft³ before allowances, the same triangle the gravel page uses.
Reference
Bag yields and loose ordering weights.
| Bag | cu ft | bags per yard |
|---|---|---|
| 0.75 cu ft bag | 0.75 | 36 |
| 1 cu ft bag | 1.00 | 27 |
| 1.5 cu ft bag | 1.50 | 18 |
| Soil | ton/yd³ | Note |
|---|---|---|
| Screened topsoil | 1.10 | About 2,200 lb/yd³ loose. Wet soil can weigh 1.4 ton/yd³. |
| Garden loam | 1.00 | About 2,000 lb/yd³. |
| Fill dirt | 1.25 | About 2,500 lb/yd³. Not a planting soil. |
Questions
How much does soil settle?
This page defaults to 10% extra volume, on top of waste. Screened topsoil that is fluffed in the truck settles when it is rained on. Ten percent is an allowance you can change, not a measured rate for your soil.
How many bags are in a yard of soil?
A 0.75 cu ft bag takes 36 per yard. A 1 cu ft bag takes 27. A 1.5 cu ft bag takes 18. The page rounds up after waste and settle.
How heavy is a yard of topsoil?
Screened topsoil is entered at 1.10 ton/yd³, about 2,200 lb. Wet soil can be nearer 1.4. Garden loam is 1.00. Fill dirt is 1.25. The ticket wins.
Sources
- Order factor (1 + waste/100) × (1 + settle/100). Cubic yard = 27 cubic feet.
- Topsoil 1.10 ton/yd³, loam 1.00, fill 1.25. Planning figures. A 10% settle allowance is a default, not a lab shrinkage test.