Topsoil vs fill dirt: what's the difference, what it weighs and how to haul it
Steve Woods · Truck Dispatcher, TruckSprint
Steve Woods is a truck dispatcher with 9 years of experience in trucking. He reviews every guide we publish. How we research and update guides.
Updated October 2026
Quick answer
Topsoil vs fill dirt comes down to organic matter. Topsoil is the dark top layer of soil, about 4% to 15% organic, used for planting. Fill dirt is subsoil and mineral soil from below, low in organic matter, used to raise grades because it compacts. Published factors put both at about 0.8 tons per loose cubic yard.
Source: WisDOT Geotechnical Manual (soil horizons); NM EMNRD conversion factors · checked 2026-10
Topsoil and fill dirt look alike in the back of a dump truck, but customers use them for opposite jobs, and mixing them up gets expensive. I'm Steve Woods, a truck dispatcher at TruckSprint with 9 years in trucking. Here's what each one is, what it weighs, how it's sold and how to haul it.
Where each one comes from
Soil forms in layers. Wisconsin DOT's geotechnical manual describes them for engineers:
| Layer | Common name | What it is |
|---|---|---|
| A horizon | Topsoil | The uppermost mineral layer, with relatively high organic content, normally about 4-15% |
| B horizon | Subsoil | Lies under the A horizon; weathered, often reddish from iron minerals |
| C horizon | Parent material | Little or no weathering; the material the upper layers formed from |
Source: Wisconsin DOT, Geotechnical Manual, Chapter 3 Section 4: Soil Development (March 1, 2017) · checked 2026-10
Topsoil comes from the A horizon, stripped off before construction and often screened before it's sold. Fill dirt is what's dug from below: subsoil and parent material from excavations, basements, ponds and road cuts.
Topsoil vs fill dirt, side by side
| Topsoil | Fill dirt | |
|---|---|---|
| Organic matter | Relatively high | Low |
| Color | Dark brown to black | Lighter: tan, red, gray |
| Main use | Lawns, gardens, landscaping, final grade | Raising grade, filling holes, backfill, building pads |
| Compacts well | No | Yes, when placed in lifts at the right moisture |
| Usually sold | Screened, by the yard | By the yard or load, sometimes free |
| Weight, published | 0.8 t/yd³ | 0.8 t/yd³ |
Source: New Mexico EMNRD, Conversion Factors for Construction Materials and Common Minerals (adapted from BLM H-3890-1) · checked 2026-10
Topsoil doesn't belong under a slab or a driveway: organic matter breaks down and compresses over time, and the ground above can settle. The usual job puts fill dirt in compacted lifts, then spreads a few inches of topsoil on top for grass.
Weight per yard and what fits in the truck
The published factor is the same for both, 0.8 tons per loose cubic yard, but moisture changes real loads more than the label does. Dry, sandy fill can come in light; wet clay can be much heavier.
Because dirt is light for its volume, the body usually fills before the weight limit:
| EXAMPLE | Tandem | Tri-axle |
|---|---|---|
| Body, struck | 14 yd³ | 16 yd³ |
| Dirt at 0.8 t/yd³ | 11.2 tons | 12.8 tons |
| EXAMPLE legal payload | 12 tons | 13.25 tons |
| What limits the load | Body volume | Body volume |
Wet material can flip that. Weigh the first load of any new dirt; the aggregate weight calculator checks yards against your legal tons, and the full weight chart is in the aggregate types guide.
How it's priced
Customers usually buy topsoil and fill by the cubic yard, delivered. Haulers are usually paid by the load, the hour or the ton, with the material priced separately. Keep the two apart on the invoice:
- Material: what the yard or site charges per yard or ton, if anything.
- Haul: your rate per load or hour for the trip.
- Extras: spreading, waiting, small-load minimums.
Screened topsoil costs more at the yard than unscreened, and fill from an excavation site may cost nothing. Local prices vary too much for a national number to be useful; call two yards before you quote.
The clean fill question
"Free fill" is only a bargain if you know where it came from. Soil from old industrial sites, demolition areas or spills can carry debris or contamination, and states regulate what can be sold or dumped as clean fill. Before you haul fill from a site you don't know, ask what the site was and whether it's been tested, and dump only where the receiving site accepts it in writing. Mixed debris is a different business; see demolition and debris hauling.
Hauling tips for dirt
- Sticky clay: wet clay hangs up in the body and can lift high and to one side when you raise it. Lower the body if it doesn't flow; see dump truck rollover prevention.
- Mud on the road: knock mud off tires and the tailgate before leaving the site. The road crew behind you will thank you.
- Cover it: dry topsoil blows; tarp it (dump truck tarp systems).
- Small jobs: backyard topsoil deliveries suit light trucks; see mini dump trucks.
Most dirt work sits alongside stone and sand on the same trucks; the full workflow is in hauling aggregate.
TruckSprint no longer dispatches dump trucks. If you also run road equipment, our desk can help it build dedicated lanes that repeat week after week.
Sources
- Wisconsin DOT, Geotechnical Manual, Chapter 3 Section 4 (March 1, 2017)
- New Mexico EMNRD, Conversion Factors for Construction Materials and Common Minerals