How this fill dirt calculator works
Any fill calculator is volume math, but dirt adds one twist the generic tools skip: compacted fill occupies less space than the loose yards on the truck, so you order more than the hole measures:
order = hole × (1 + compaction%) · 15% typical, up to the ¼ yd³
The order rounds to the quarter yard, the weight line converts at 1.1 tons per yard so you know what’s rolling in, and the truck counter divides by the 10 yd³ a tandem hauls. At the defaults — a 20 × 10 ft low spot brought up 6 in — that’s 4.5 yd³, one truck, about $113; the line-by-line math is in the worked example below.
What kind of fill dirt should I order?
“Fill” covers everything from engineered structural material to whatever came out of a pool dig — and since it all looks like dirt on the truck, order by name:
Common fill / bank run
Unprocessed subsoil straight from an excavation: rocks, clods and all. The cheapest yard on the market and fine deep in a big fill, where nothing will ever see it.
Screened fill
The same subsoil run over a screen to pull rocks and debris — worth the upcharge for the top foot of any fill you’ll grade, rake or mow over.
Select / structural fill
Specified granular material with a known gradation that compacts predictably — what engineers call for under slabs, footings and retaining walls. If a drawing says “compacted structural fill,” this is that, and its testing matters as much as its price.
Sand fill
Damp pit sand for trench bedding and wet sites — it drains where clay fill puddles. Cheap, heavy, and the right call around pipes and behind walls that need to weep.
Free fill (with eyes open)
Contractors with spoil to dump will often deliver for nothing. Sometimes that’s clean clay worth every penny of free; sometimes it’s construction debris with buried sod that will sink for a decade. Look at the pile before it lands, and never accept organic material in a structural fill.
| Product | Typical range |
|---|---|
| Common fill / bank run | $10–25 |
| Screened fill | $20–35 |
| Select / structural | $25–50 |
| Sand fill | $15–30 |
| Contractor spoil | $0 — caveat emptor |
Why compaction decides how much fill dirt you need
Compaction is the whole reason this calculator over-orders: dirt placed loose is 10–25% air, and that air leaves — either now under a compactor, or slowly under your shed. The rules that make fill permanent:
- Lifts, not piles: place 6–8 in of loose dirt, compact it, repeat. A plate compactor handles lifts; nothing hand-held fixes a 3 ft loose dump.
- Moisture matters: fill compacts best slightly damp — dust won’t pack and mud pumps. Squeeze a handful: it should ball, not drip.
- Set the allowance by soil: 10% for granular/sandy fill, 15% typical mixed subsoil, 20–25% for cloddy clay placed in thick lifts.
- Flooding is not compacting: water-settling helps sand a little and clay not at all — the compactor is the tool.
- Know when it’s engineering: fills over about 2 ft under anything structural, or any fill behind a retaining wall, deserve a compaction spec and testing, not a guess.
How many yards of fill dirt per square foot?
Table 2 turns common fills into orders at the 15% default; Table 3 sorts the dirt family by job. Both follow this calculator’s engine at 1.1 t/yd³.
| Area × depth | Order | ≈ Tons |
|---|---|---|
| 100 ft² @ 6″ | 2.25 yd³ | 2.48 |
| 200 ft² @ 6″ | 4.5 yd³ | 4.95 |
| 500 ft² @ 6″ | 10.75 yd³ | 11.83 |
| 1,000 ft² @ 4″ | 14.25 yd³ | 15.68 |
| 1,000 ft² @ 12″ | 42.75 yd³ | 47.03 |
| Material | Use it for |
|---|---|
| Fill dirt | Grades, holes, under slabs |
| Topsoil | Top 4–6″ where plants grow |
| Screened fill | Final grading, fewer rocks |
| Structural fill | Engineered lifts, spec jobs |
How to measure for fill dirt
Holes are never as regular as the tape hopes — measure the depth in several places and average before you order trucks. Dimension fields take feet-inches (20, 20 ft 6 in) or metric (6 m).
- Measure the area’s length and width. Sprawling regrades break into rectangles — total them with the square footage calculator and order once.
- Find the real depth with a stringline: stretch a line at finish grade, measure down to existing ground on a grid of spots, and average the readings. One deep corner skews a single measurement badly.
- Set the compaction allowance by soil — 10% sandy, 15% typical, 20%+ cloddy clay — per the compaction section above.
- Order by the yard, delivered. Note the truck count: each tandem load is a driveway full of dirt that has to land somewhere spreadable.
- Plan the topsoil cap separately if anything will grow there — 4–6 in via the topsoil calculator, ordered after the fill is compacted.
- Check the weight line before promising your pickup: at 1.1 t/yd³, even the small default job is nearly 5 tons.
Worked example: fill for a 20 × 10 ft low spot
The defaults, worked line by line — 200 ft² brought up 6 in, 15% compaction, $25 a yard:
hole = 200 × (6 ÷ 12) = 100 ft³ = 100 ÷ 27 = 3.7 yd³
compaction = 3.7 × 1.15 = 4.26 → order 4.5 yd³ (¼-yd rounding)
weight = 4.5 × 1.1 = 4.95 tons
trucks = 4.5 ÷ 10 → 1 tandem load
cost = 4.5 × $25 = $113
The 0.8 yd³ the compaction allowance added is not padding — it’s the air that leaves the loose dirt under the compactor. Order the bare 3.7 and the spot reads full the day you finish, then sits an inch low by spring with the truck long gone.
What this fill dirt estimate doesn’t include
The calculator prices the dirt on the truck. Turning a pile into a finished grade has its own lines:
- Spreading and grading. Skid-steer or tractor time on anything past wheelbarrow scale — hired machine work commonly runs $75–150 an hour.
- Compaction equipment. Plate compactor rental about $90–120 a day; big fills want a trench roller or ride-on.
- The topsoil cap. 4–6 in of growing layer over the fill wherever grass or beds follow.
- Erosion control. Straw, matting or silt fence while the new grade knits in — required by many jurisdictions on slopes.
- Grading permits. Many municipalities regulate fills past a threshold (commonly around 50 yd³ or near property lines and drainage ways) — ask before the convoy arrives.
- Drainage work. Raising grade moves water; swales, pipe or a dry well may be the real project.
Fill dirt FAQ
How much fill dirt do I need?
Multiply area by depth in feet, divide by 27, then add compaction: a 20 × 10 ft area filled 6 in deep measures 3.7 yd³, and with 15% compaction the order is 4.5 cubic yards — about 4.95 tons, one truck load, roughly $113 at $25 a yard.
How much fill dirt to raise my yard 12 inches?
Figure 42.75 yd³ per 1,000 ft² with 15% compaction — four to five tandem loads and about $1,069 at $25 a yard. Big raises go in compacted 6–8 in lifts, and anything against a foundation needs the grade sloping away when you finish.
How many tons is a yard of fill dirt?
About 1.1 tons — fill dirt runs roughly 2,200 lb per cubic yard as an estimating average. Wet clay pushes past 2,500 lb and dry sandy fill drops under 2,000, which is why suppliers quote dirt by the yard, not the ton.
Why order more dirt than the hole measures?
Because compacted dirt takes up less space than loose dirt — it settles 10–25% as it packs. Fill placed loose and left to settle on its own drops for years; fill compacted in 6–8 in lifts settles now, while you still have dirt on site to top it up.
Can I use fill dirt under a concrete slab?
Yes, when it goes in right: clean mineral fill, compacted in 6–8 in lifts, capped with 4 in of gravel under the pour. Loose-dumped or organic fill settles and cracks the slab above it, and fills deeper than about 2 ft under structures are worth an engineer’s eye.
How much does fill dirt cost?
Commonly $15–40 per cubic yard delivered in 2026, and sometimes near-free from excavation contractors who need somewhere to put spoil — quality varies exactly as much as the price. The default job is about $113 at the editable $25 default.
What is the difference between fill dirt and topsoil?
Fill dirt is subsoil — mineral, low-organic, stable under load, right for grades, holes and under slabs. Topsoil is the organic growing layer: it feeds lawns but keeps decomposing and settling, so it never goes under anything structural. Fill deep, then cap with 4–6 in of topsoil where things must grow.
How many yards of dirt fit in a dump truck?
A tandem-axle dump truck hauls about 10–14 cubic yards of dirt; a single-axle runs 5–6. The calculator counts loads at 10 yd³ so the truck math stays conservative — big regrades go from “a few trips” to “a convoy” fast.
Sources and standards
The compaction figures and practice on this page follow standard earthwork references:
- ASTM D698 (standard Proctor): the compaction test behind “95% compaction” specs on engineered fills.
- Common earthwork practice: the 6–8 in lift, near-optimum-moisture placement rule used across site work.
- Supplier truck capacities: the 10 yd³ tandem figure is the conservative end of published body volumes — your hauler’s truck may carry more.
- Local grading ordinances: fill-volume permit thresholds vary by jurisdiction — the building department’s number governs, not this page’s example.
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