Fill Dirt Calculator: Cubic Yards of Dirt for Any Project

Fill Dirt vs. Topsoil

Fill dirt and topsoil solve completely different problems, even though both arrive on a truck looking like plain brown soil. Fill dirt is a structural material with little to no organic matter, is chosen for how predictably it compacts, and is never meant to grow anything in. It's typically excavated subsoil, sometimes screened to remove large rocks and debris, sometimes not, depending on the source and the job.

Topsoil is a biological material, chosen specifically for the organic matter, nutrients and microbial life that make it able to grow plants, and it costs more per cubic yard than fill dirt for exactly that reason. Buying topsoil for a job that only needs structural fill wastes money on qualities the job will never use; buying fill dirt for a planting bed leaves you with soil that can't support anything you put in it.

The practical rule: if something is going to grow in it, it needs topsoil. If it's going under something, such as a slab, a lawn's subgrade, or a wall's backfill, fill dirt is the cheaper, correct choice.

Some suppliers blur the line by selling "fill dirt" that is really just cheap, unscreened topsoil with the label swapped, or "topsoil" that is closer to screened fill dirt with a bit of compost mixed through it. Asking directly whether the material has been tested or amended for growing, rather than trusting the name on the invoice, is the only reliable way to know which one you're actually getting.

When to Use Fill Dirt

Fill dirt shows up on almost every kind of property project that reshapes ground rather than growing something in it, precisely because it's the cheapest material that still compacts predictably enough to build on or around. Four situations account for most fill dirt orders:

Grading a sloped yard is the most common residential use: fill dirt builds up low corners so water runs away from a foundation instead of pooling against it. A slope of even 2 to 3 percent, roughly a 2 to 3 inch drop over 10 feet, moving away from the house is usually enough to keep water from pooling against a foundation wall, and fill dirt is the standard material for building that slope where the existing grade runs flat or, worse, tilts toward the house instead of away from it.

Retaining wall backfill is a more technical use, since the wall is engineered to hold a specific weight and type of material in place, and swapping in a denser fill than the wall was designed for can overload it. Most retaining wall specifications call for a free-draining fill directly behind the wall, sometimes gravel rather than dirt at all, precisely because trapped water pushing against the back of a wall is a more common cause of wall failure than the weight of the soil itself.

Material Density Reference

Density is the one number that changes the delivered weight without changing the volume you order, and it's the reason the same "2 cubic yards of fill" quote can arrive as very different weights depending on which material the supplier actually loads onto the truck. Clay is the densest common fill material, which makes it the heaviest to haul but also the most effective at holding a compacted shape once it's in place:

The Compaction Factor

Fill dirt settles more after delivery than topsoil does, and by a wider margin, because it's denser and less structured to begin with. Topsoil has organic matter and a crumb structure that resists settling somewhat on its own; fill dirt is closer to raw mineral soil with no such structure, so the weight of what's piled on top of it, whether more fill, a compacted base layer, or eventually a structure, presses it down further than the same depth of topsoil would settle.

The standard allowance is 10 to 15 percent more fill than the raw calculated volume, which is exactly what the calculator's "Recommended Order" figure adds automatically. Ordering the raw volume with no allowance is the single most common reason a grading job comes up short on delivery day and needs a second, smaller order at a worse per-yard price than the first.

Compaction equipment changes how much of that settling happens before you ever see it, not just how much happens afterward. Fill spread and left loose settles under its own weight and rainfall over weeks or months; fill compacted in layers with a plate compactor or roller during placement reaches most of its final density immediately, which is exactly why engineered applications like a driveway base specify compaction in lifts rather than dumping the full depth in one pass and walking away.

Fill Dirt Cost Estimate

Fill dirt is one of the cheapest bulk materials sold by the yard, but cost scales with project size the same way any other soil order does. Bagged material is convenient for a small patch and expensive for anything larger:

Past a couple of cubic yards, bagged fill dirt is rarely sold at all. Most garden centres stock topsoil and compost in bags but not plain fill, since the jobs it's used for are almost always large enough to justify a bulk delivery in the first place. For an ordinary garden project, the homepage calculator covers topsoil volume and weight the same way this page covers fill dirt.

Delivery fees sit on top of every figure in that table and vary far more by location than the material cost itself does. A supplier five minutes from the job site might deliver for free above a minimum order size, while the same load trucked across a metro area can add $100 or more regardless of how small the order is. Always ask for the delivered price, not just the per-yard material price, before comparing two quotes against each other.

Getting an Accurate Quote

Give a supplier the calculator's cubic yard figure directly rather than the raw dimensions of the area. It removes any chance of a mismatch between how you measured and how they price. If the project involves a retaining wall or another engineered structure, mention that up front as well, since some suppliers stock separate select fill or engineered fill specifically for that kind of job and won't offer it unless asked. A supplier who quotes without ever asking what the fill is for is worth a follow-up question before the order is placed, not after the truck has already arrived.

Frequently Asked Questions