Enter the area and choose the job. We’ll set a practical depth and tell you how much dirt to order.
Fill dirt is subsoil — the layer below the growing zone, with the organic matter screened out or long since gone. It is sold to occupy volume and hold its shape, which is exactly what topsoil cannot do.
That absence of organic matter is a feature here. Organics decompose, and as they decompose the soil above them subsides. Fill a 2 foot hole with topsoil and you will be filling it again in three years. Fill it with fill dirt and it stays where you put it.
The trade-off is that nothing grows in it, so anything that needs to support plants gets a cap of 4 to 6 inches of topsoil over the fill. Buy the bulk volume as fill and the finish layer as topsoil — it costs less and performs better than either one alone.
Loose fill dirt shrinks when it compacts. Depending on soil type and how hard it is compacted, expect to lose roughly 15 to 25 percent of the loose volume, and more in clay. A hole that measures 10 cubic yards needs somewhere around 12 yards of loose dirt delivered to finish flush.
The calculator adds a waste allowance on top of your measured volume, and ticking the compaction box increases it further. Neither figure can know your soil, so treat the result as a planning number and expect to be within a load rather than exact.
Compaction is not optional on anything structural. Fill in lifts of 6 to 8 inches and compact each one before the next — a full trench backfilled loose and left to settle will subside for years and can undermine whatever sits on it. On soft or clay soil, moisten each lift lightly before compacting; bone-dry clay will not knit together.
The standard target is a fall of about 6 inches over the first 10 feet away from the foundation — roughly a 5 percent slope. That is the figure most residential codes work from, and it exists because water sitting against a foundation is the origin of most wet basements.
Keep the finished soil at least 6 inches below any siding, brick ledge or sill plate. Piling dirt up against siding to fix a grade creates a moisture and termite path straight into the wall framing, and it is a common and expensive mistake.
Measure the fall with a level on a straight board, or a string line and a tape, before ordering. A 10 by 40 foot strip regraded to that slope needs about 2.5 cubic yards once you account for the wedge shape — measure the average depth, not the deepest point.
For a rectangular excavation, use the length and width of the opening and the average depth. Average, not deepest: most holes are bowl-shaped and using the deepest measurement overshoots badly.
Round holes — a removed tree stump, an old pool — are easier entered as a circle using the diameter across the widest point. Sloped-sided holes are close enough if you average the top and bottom widths.
A trench is length times width times depth, and it is worth checking the width against reality rather than the plan. Machine-dug trenches come out wider than specified, sometimes by half again, and that difference is real material you have to buy.
Where fill dirt is genuinely cheap, ordering a little long is usually the right call. A short load leaves you with a partly filled hole and a second delivery charge that costs more than the extra dirt would have.
Volume is area multiplied by depth. Weight is that volume multiplied by the material's density.
volume = area × depth
tons = volume (cu ft) × 76 lb/cu ft ÷ 2000
order = volume × 1.05Density used: 76 lb per cubic foot. Loose fill dirt, typical 70–85 lb/ft³. Actual delivered weight varies with moisture and stone size, so treat tonnage as an estimate and confirm with your supplier.
The recommended order adds 5% on top. Material settles, ground is never perfectly flat, and a second delivery costs far more than a little extra dirt.
Fill dirt is subsoil with the organic matter screened out — inert, cheap, and it compacts well, which is exactly what you want under a structure or filling a hole. Topsoil has organic content and is what plants grow in. Using topsoil as bulk fill is expensive and it settles more.
Around 2,000 lb per cubic yard loose, more once wet or compacted. A standard half-ton pickup should not carry a full cubic yard of it.
Because loose dirt loses volume when you tamp it. Fill that is not compacted in layers will sink later, leaving you with the same low spot you were trying to fix. Plan on roughly 15% more loose material than the finished volume, and compact every 4 in as you fill.
Enter the hole's actual depth rather than a landscaping depth, and use its length and width at the widest point. Holes are rarely neat rectangles, so round up — being a wheelbarrow short is worse than being one over.