Soil volume estimator
Topsoil calculator
Enter the size of the bed, lawn or planter and how deep the soil needs to go, and this returns the volume in cubic yards — the unit every soil yard sells by — along with cubic feet, cubic metres, weight in tons, bag counts and an optional cost estimate.
Soil is the material people most often under-order, because a bed that looks shallow swallows a surprising amount once you fill it properly. Measure, then check the coverage table below before you call the yard.
How much topsoil do I need?
Multiply the area you are covering by the depth you want, in consistent units, then convert to cubic yards by dividing the cubic feet by 27. That is the entire method; the calculator just handles the unit juggling so a bed measured in feet with a depth given in inches comes out right.
Worked example: a raised bed 8 ft by 4 ft, filled 12 inches deep. The area is 32 square feet, the depth is 1 foot, so the volume is 32 cubic feet, which is 32 ÷ 27 = 1.19 cubic yards — about 1.4 tons of screened topsoil. Add 10% for settling and you are ordering 1.3 yards, which in practice means asking for a yard and a half.
Second example, this time a thin layer over a lot of ground: top-dressing 1,000 square feet of lawn at 1/4 inch. That is 1,000 × 0.0208 = 20.8 cubic feet, or 0.77 cubic yards. Barely a yard covers a large lawn at dressing depth — which is exactly why people who guess tend to order far too much for lawn work and far too little for beds.
Topsoil in yards, quickly. One cubic yard = 27 cubic feet. One cubic yard of screened topsoil weighs roughly 1.1–1.3 US tons, and covers 108 square feet at 3 inches deep or 81 square feet at 4 inches. It is also 54 of the half-cubic-foot bags sold at garden centres, which is why bulk delivery wins for anything past a wheelbarrow or two.
Topsoil coverage: what one cubic yard covers
Coverage falls out of a single division: 324 divided by the depth in inches gives the square feet one cubic yard will cover. The table below is that formula worked out at the depths people actually use.
| Depth | 1 yd³ covers | 100 sq ft needs | 1,000 sq ft needs |
|---|---|---|---|
| 1/4 in (top-dressing) | 1,296 sq ft | 0.08 yd³ | 0.77 yd³ |
| 1/2 in | 648 sq ft | 0.15 yd³ | 1.54 yd³ |
| 1 in | 324 sq ft | 0.31 yd³ | 3.09 yd³ |
| 2 in | 162 sq ft | 0.62 yd³ | 6.17 yd³ |
| 3 in | 108 sq ft | 0.93 yd³ | 9.26 yd³ |
| 4 in | 81 sq ft | 1.23 yd³ | 12.35 yd³ |
| 6 in | 54 sq ft | 1.85 yd³ | 18.52 yd³ |
| 12 in | 27 sq ft | 3.70 yd³ | 37.04 yd³ |
How deep should the topsoil go?
- Lawn top-dressing: 1/4 to 1/2 inch. Any more and you smother the grass. Rake it into the sward rather than laying it as a blanket.
- Levelling low spots in a lawn: up to 1 inch per pass, repeated across seasons. Deeper than that and you kill what is underneath, so strip the sod instead.
- New lawn from seed or sod: 4 to 6 inches of good soil over the subgrade.
- Flower and shrub beds: 6 to 12 inches, depending on what is going in.
- Vegetable beds and raised planters: 12 inches or more. Deep-rooting crops such as carrots and parsnips want the full foot of loose soil.
Topsoil, garden soil, compost and fill dirt
These are priced and weighed differently, so the label on the quote matters. Screened topsoil is native soil run through a screen to pull out stones and roots — the default for beds and lawns. Garden soil or a planting mix is topsoil blended with compost; it is lighter, richer and typically more expensive. Compost on its own is lighter again, around 0.8 tons per yard, and should be mixed in rather than used as the whole fill. Fill dirt is unscreened subsoil for raising grade — cheap, heavy, and not something to plant in.
For a raised bed, a common recipe is roughly 60% screened topsoil, 30% compost and 10% coarse material such as perlite or sand. Run the total bed volume through the calculator once, then split that yardage between the components.
Common questions
How many cubic yards of topsoil for a 20 ft × 20 ft bed at 6 inches?
400 square feet × 0.5 ft = 200 cubic feet = 7.41 cubic yards, roughly 8.9 tons at 1.2 tons per yard. Add 10% for settling and you are ordering about 8 yards.
How much does a cubic yard of topsoil weigh?
Typically 1.1 to 1.3 US tons — call it around 2,200 to 2,600 pounds — for screened soil that is dry to slightly moist. Wet soil is much heavier and can approach 1.5 tons per yard, which matters if you are hiring a truck with a weight limit or wheeling it across a lawn.
How many bags of topsoil equal a cubic yard?
54 bags at 0.5 cubic feet, 36 bags at 0.75 cubic feet, or 27 bags at 1 cubic foot. Bagged soil is often sold by weight instead — a 40 lb bag holds roughly 0.5 cubic feet of typical topsoil, so figure on about 50 of them per yard. Bulk delivery is almost always cheaper past half a yard, once you have a way to move it.
Should I add extra for settling?
For beds and planters, yes: 10–20%. Freshly delivered soil is fluffed from handling and compresses once it is watered in. For thin lawn dressing there is nothing to settle, so leave the allowance at zero. The settling field simply scales every output by the percentage you type.
Can I calculate several beds at once?
Yes — use Add another bed for each one. They share a single depth, so if your beds are different depths, run them in separate passes and add the yardages, or work out the deepest group first. Circular planters are handled by switching a block to Circle and entering the diameter.