Topsoil Calculator
This topsoil calculator works out how much a lawn, garden bed or raised bed needs, in cubic yards, plus bags and an estimated weight for ordering.
Garden Bed or Lawn Area
Raised Beds
Fill one bed or a whole row of identical beds, and see the figure in bags as well as yards.
Topsoil Cost
How to use the Topsoil Calculator
How deep the soil needs to be is the first question, and it depends on what will grow in it. Top-dressing a lawn takes a quarter to half an inch at a time; a new planting bed usually wants four to six inches of good soil over whatever is already there; a raised bed is filled to within an inch or two of the top rail.
Pick the soil type. It does not change the volume at all, only the estimated weight, and the price if your supplier sells by the ton. Order by the cubic yard where you can.
The raised bed tab multiplies one bed by however many identical beds you are filling, and converts the total into bagged soil as well as bulk yards.
Topsoil formula
Volume is plain geometry:
volume = length × width × depthcubic yards = cubic feet ÷ 27- Raised beds:
total = one bed × number of beds
Bags and weight follow from the volume:
bags = cubic feet ÷ bag size, rounded uptons = cubic yards × lb per cubic yard ÷ 2,000
| Soil type | Approx. lb per cubic yard | Tons per yard |
|---|---|---|
| Screened topsoil | 2,100 | 1.05 |
| Garden soil blend | 1,500 | 0.75 |
| Raised bed mix | 1,300 | 0.65 |
| Compost | 1,100 | 0.55 |
| Fill dirt | 2,300 | 1.15 |
Worked example
A 20 ft × 10 ft bed topped with 4 inches of screened topsoil, 10% settling allowance:
- Area: 20 × 10 = 200 sq ft
- Depth: 4 in = 0.3333 ft. Volume: 200 × 0.3333 = 66.67 ft³
- Cubic yards: 66.67 ÷ 27 = 2.47, plus 10% = 2.72 yd³
- Weight: 2.72 × 2,100 = 5,704 lb = 2.85 tons
Two raised beds at 8 ft × 4 ft × 12 in deep come to 64 ft³, which is 2.37 yd³ before settling, or 43 bags at 1.5 cubic feet each.
What the result means
The cubic yard figure is exact. The tonnage is an estimate, and a rougher one than for gravel. Published densities for topsoil range from roughly 1,000 to 2,700 lb per cubic yard, and that spread is not sloppiness, it is the difference between a peat and compost blend sold for raised beds and a screened mineral topsoil sold by the truckload. Moisture moves the weight again on top of that.
So order by volume. If a supplier only sells by weight, ask what a cubic yard of their material weighs rather than trusting a generic chart.
Bagged soil is convenient and several times the price of bulk per cubic foot. The crossover is usually around one cubic yard, past that, bulk delivery normally wins even after the delivery fee.
Common mistakes
- Filling a raised bed entirely with topsoil. Straight topsoil compacts in a container and drains poorly. Most raised bed recipes are closer to a third compost, with the rest a lighter blend.
- Measuring the frame instead of the fill. A 12 inch frame is filled to about 10 or 11 inches so water does not run over the edge.
- Forgetting that soil settles. Fresh soil drops noticeably after the first few waterings, which is what the settling allowance covers.
- Top-dressing a lawn too thickly. A quarter to half an inch at a time, burying the grass crowns kills it.
- Confusing fill dirt with topsoil. Fill dirt is subsoil: cheap, and meant for raising grade rather than growing in.
Frequently asked questions
How many cubic yards of topsoil do I need?
Multiply length by width by depth in feet, then divide by 27. A 20 by 10 foot bed at 4 inches deep is 66.7 cubic feet, or 2.47 cubic yards before any settling allowance.
How much does a cubic yard of topsoil weigh?
A screened mineral topsoil runs around 2,000 to 2,200 lb per cubic yard, so roughly one ton. Compost-heavy garden and raised bed blends are much lighter, often 1,100 to 1,500 lb. Wet material is heavier again. Check with your supplier before ordering by weight.
How much topsoil do I need for a raised bed?
An 8 by 4 foot bed filled 12 inches deep takes 32 cubic feet, which is 1.19 cubic yards or 22 bags at 1.5 cubic feet each. Two such beds come to 2.37 cubic yards.
How deep should topsoil be?
A quarter to half an inch for top-dressing an existing lawn. Four to six inches for a new lawn or planting bed. Twelve inches or more for deep-rooted vegetables and shrubs.
How many bags of topsoil are in a cubic yard?
A cubic yard is 27 cubic feet, so 36 bags at 0.75 cubic feet, 27 at 1 cubic foot, 18 at 1.5 cubic feet, or 14 at 2 cubic feet.
Is topsoil the same as garden soil?
No. Topsoil is screened native soil sold in bulk. Garden soil is topsoil already amended with compost and other organic matter, sold at a higher price and usually in bags. Raised bed mixes are lighter still and drain faster.
Sources and assumptions
Volume is exact geometry. Densities are mid-range values taken from landscape supply charts, which place screened topsoil at roughly 2,000 to 2,200 lb per cubic yard and compost-based blends considerably lower. That is the figure for moist screened topsoil as delivered, which is what suppliers actually quote. Dry loose material is much lighter, Caterpillar publishes 1,600 lb per cubic yard for loose topsoil and 2,300 in the bank, so treat 2,100 as the top of a wide range rather than a constant.
Sources for topsoil disagree by about a factor of two, because the name covers materials from a peat-and-compost raised bed mix to a heavy mineral subsoil blend. This calculator therefore leads with cubic yards and labels tonnage as an estimate.
Confirm quantities, and the supplier’s own weight conversion, before ordering.