How this calculator works
It multiplies the area by the depth to get the volume of soil, adds an allowance for settling and compaction, and rounds up to whole cubic yards (cubic metres in metric) or whole bags.
Loose topsoil settles noticeably once it is raked, rolled and watered, so the default allowance is 15%. Bag counts use the volume printed on the bag; 0.75 cu ft is a common size in the US and the metric default is 50 litres.
area = length × width
cu ft = area × depth (in) ÷ 12
bulk cu yd = cu ft × (1 + settling) ÷ 27
bags = cu ft × (1 + settling) ÷ cu ft per bagWorked example
A 20′ × 10′ area is 200 sq ft. Spreading 4″ of topsoil takes 200 × 4 ÷ 12 = 66.7 cu ft, or 2.47 cu yd. With 15% for settling that is 2.84 cu yd, so the order is 3 cu yd of bulk topsoil.
Tips before you buy
- For a new lawn, 4–6″ of good topsoil is the usual target; for leveling low spots, measure the depth of each dip.
- Bulk soil is heavy. Have it dumped as close to the work as possible and keep it off the driveway edge if you can.
- Ask whether the soil is screened. Screened topsoil spreads evenly and has fewer stones and roots.
- Raised beds are measured the same way: inside length × inside width × fill depth.
Questions
- How many bags of topsoil equal a cubic yard?
- A cubic yard is 27 cubic feet, so it takes 36 bags of 0.75 cubic feet or 27 bags of 1 cubic foot. For more than a yard or two, bulk soil is usually far less work to buy and haul.
- How much does a cubic yard of topsoil weigh?
- Dry topsoil weighs roughly a ton per cubic yard, and wet soil can be noticeably heavier. That is more than many pickups can carry in one load, so check your vehicle’s payload rating before hauling it yourself.
- Why add 15% for settling?
- Loose soil contains air. After it is raked, rolled and watered it compacts and the surface drops. Ordering a little extra keeps the finished grade where you want it.