A soil calculator has to answer in two units
Soil is straightforward geometry until you try to weigh it. Volume is the surface you are covering multiplied by how deep you want it, and that part never changes — it is the same arithmetic whether you call it topsoil, garden soil or fill. Weight is where it gets slippery, because screened soil holds water and the same yard can arrive anywhere between 1,900 and 2,300 pounds depending on when it last rained.
That matters because soil is quoted both ways. A landscape yard sells by the cubic yard; a bulk haulier prices by the ton. This page gives you both, and says plainly that the ton figure is a band rather than a number.
- depth — finished soil depth in inches, not the height of the frame
- fill depth — how far up a raised bed you actually fill, usually short of the rim
- density — 1,900 to 2,300 lb per cubic yard, with no published typical figure
Worked example: three 8 by 4 foot beds filled 10 inches
Just under three yards for three standard beds. That is a tipper load rather than something you carry home, which is the usual moment gardeners discover raised beds are a bulk purchase.
Why no weight is shown by default
Aggregates have a published typical density. Screened soil does not, and inventing one by averaging the ends of the range would be a guess dressed up as a figure. A yard at the wet end weighs a fifth more than the same yard at the dry end, which matters when a supplier is charging by the ton or your trailer has a plated limit. Enter your supplier's number and the weight appears.
Common mistakes
- Filling to the top of the frame. Soil sits proud, then washes over the edge every time it rains. Fill an inch or two short.
- Not allowing for settlement. Fresh soil drops in its first season and beds that looked full in spring look mean by autumn. How far is not something anyone publishes — top up rather than guess.
- Buying screened soil for the whole depth. The bottom half of a deep bed can be cheaper as-dug soil or compost; screened topsoil is worth paying for near the surface.
- Measuring outside the frame. Six-inch sleepers on an eight by four bed swallow a foot of length and width between them.
When these numbers do not apply
- Lawn topdressing. That goes on at a fraction of an inch and is measured by the bag, not the yard.
- Beds with a hügelkultur or rubble base. Anything filling the bottom displaces soil you would otherwise buy.
- Compost and soil blends. These are lighter than screened topsoil and follow their own densities.
- Sloping ground. A level finish over a slope needs considerably more at the low end than an average depth suggests.
Beds and coverings
Filling raised beds rather than dressing open ground is a different calculation, because a bed has a count and a fill depth that is deliberately not the frame height — the raised bed soil calculator handles that. Once the soil is in, the mulch calculator covers what goes on top to hold moisture in.
Topsoil for 500 ft², by depth
| Depth | Cubic yards | ft² one yard covers | Tons |
|---|---|---|---|
| 1 in | 1.54 | 324 | — |
| 2 in | 3.09 | 162 | — |
| 3 in | 4.63 | 108 | — |
| 4 in | 6.17 | 81 | — |
| 6 in | 9.26 | 54 | — |
| 12 in | 18.52 | 27 | — |
Topdressing a lawn takes 1–2 in; a new lawn or bed wants 4–6 in. Fresh soil settles in its first season by an amount nobody publishes, so plan to top up rather than over-filling.
