The pile is the part nobody draws
Strip 6 in of topsoil off a 6,000 sq ft building area and you have 111.1 cubic yards in bank measure. Break it loose and it is 138.9. Stack that at a 34 degree repose angle to a working height of 8 ft as a windrow and the result is a ridge 27 ft long with a half cone on each end, 50.8 ft overall, 23.7 ft wide, standing on 1,085 sq ft.
That is 18 percent of the ground you just stripped, occupied for the duration of the job by material you are not allowed to lose. On a tight lot it is the difference between a workable site and one where the pile gets moved three times. Moving a pile is the purest form of wasted money in earthwork: the material ends up exactly where it started, in a different corner.
Three volumes, and the respread is the fourth number
| State | What it is | Default figures |
|---|---|---|
| Bank | Sitting undisturbed in the ground. What the strip depth measures. | 111.1 cu yd |
| Loose | Broken up and piled. What a truck box and a stockpile measure. | 138.9 cu yd |
| Spread loose | Raked out over the respread area before anything settles. | 10.7 in over 4,200 sq ft |
| Finished | After settlement and rain. | 9.1 in |
Notice that 6 in stripped does not come back as 6 in even before the area changes. At 25 percent swell and 15 percent settlement the round trip multiplies by 1.0625, so over the same footprint you would finish about 6.4 in proud. The two factors describe different events — one is what a bucket does to the soil structure, the other is what gravity and rain undo over a season — and there is no reason for them to cancel. Only measurement settles it, and the measurement is yours.
The respread area moves it much further. Strip 6,000 sq ft, build a house and a drive, and you are respreading over 4,200. The same material over 70 percent of the ground goes on half again as deep, which is how a job that started out saving topsoil ends up with 9 in of it over the lawn and a surplus nobody planned to haul.
What the surplus really costs
At a 4 in finished target over 4,200 sq ft, the target needs 61 loose cubic yards. The pile holds 138.9. That leaves 77.9 loose yards surplus, seven truck loads, and the same pile would have covered 9,563 sq ft at 4 in if there were that much ground to put it on. Either you find somewhere on site for it, or it goes on trucks, and topsoil is one of the few excavated materials that is genuinely worth something to somebody else.
Where it may legally go is a local question, and it is a real one — clean fill, imported soil and spoil disposal are regulated in a lot of places, and near a watercourse or a wetland the rules get sharper. That is a call to the local building or stormwater authority, not something a volume calculator can answer.
Where the geometry stops being reliable
A stockpile is modelled here as a ridge of material standing at one angle with a half cone on each end. It is a good approximation of a pile pushed up neatly and a poor one of a pile that got rained on, driven over, or dumped in a hurry from the back of a truck. Wet material slumps and its footprint grows. Material with root mat and sod in it stands steeper than the same soil screened.
Two things the geometry is silent on and should be. It says nothing about how close the pile may stand to an open excavation, because a stockpile beside a dig is a surcharge on that edge and that is a competent-person decision made on the ground looking at the actual soil. And it says nothing about whether the pile is stable, because piles are not designed, they are made by a machine operator, and any question about a slope standing up belongs to an engineer.
Questions people ask
How much ground does a topsoil stockpile take?
More than people expect, and it goes with the volume rather than with the area you stripped. The 138.9 loose cubic yards from a 6,000 sq ft strip at 6 in, windrowed 8 ft high at a 34 degree repose angle, covers 1,085 sq ft — about 18 percent of the ground it came off. Raise the working height and the footprint drops fast, because the volume of a pile goes with the cube of its height while its footprint goes with the square. Lower the repose angle, which is what wet material does, and the footprint grows.
Why does 6 inches stripped not go back as 6 inches?
Because two different factors act on it and they do not cancel. Swell is what happens when a bucket breaks the soil structure and air gets in between the particles, so 111 bank yards becomes 139 loose. Settlement is what happens over the following season as the spread material consolidates and takes rain. At the defaults here — 25 percent swell, 15 percent settlement — the round trip comes out 6.4 percent proud over the same area. Change the respread area and the depth moves a great deal more than that.
What angle of repose should I use for topsoil?
Whatever your own material stands at, which you can measure in twenty minutes with a level and a tape on a pile that already exists. It is not a constant. The same soil dry, wet, screened and full of root mat gives four different angles, and it changes again after a week of rain. The figure in the form is a placeholder. If you have never measured one, run the calculation at two angles a few degrees apart and see how much the footprint moves — that tells you whether the number matters for your site.
Is it worth stripping and saving the topsoil at all?
That is a judgement about your soil and your budget rather than an arithmetic result, but the quantities help. The surplus at the default settings is 77.9 loose yards, which is seven truck loads either way — seven loads out if you strip and cannot use it, or seven loads in if you did not strip and have to buy it. Topsoil is also the one excavated material with real resale value. What the page cannot tell you is whether the soil under your lawn is worth saving, which depends on what is in it.
Can I stack the pile higher to save space?
The arithmetic says yes and says so strongly — a pile is a cone or a ridge, so doubling the height cuts the footprint far more than half. What decides it is not arithmetic. It is what the machine can reach, whether anybody has to work beside it, how the material behaves wet, and how close the pile stands to an excavation, a wall, a property line or a road. A stockpile next to an open dig is a load on that edge. None of those are questions this page answers, and the height field is there for you to put your own limit into rather than to find one.