Fill Dirt Calculator
Fill dirt is cheap subsoil used to fill holes, raise low ground and backfill — not to grow anything in. Work out how many cubic yards you need below.
Sets a typical depth — tweak anything below.
For a 20 ft × 10 ft area at 2 in deep, order about 1.54 cubic yards (1.95 US tons) of fill dirt.
Estimates only. Densities vary by moisture, compaction and supplier — confirm quantities before ordering.
What is fill dirt?
Fill dirt is subsoil — the dirt from below the growing layer, with the organic matter screened out or simply absent. That's the whole point: no organic matter means nothing in it rots away, so it stays put and holds its shape once compacted. It's the cheapest dirt you can buy, usually unscreened, and often comes with rocks and clay in it.
What is fill dirt used for?
Use it for volume and structure: filling holes, raising a low spot, building up grade around a foundation, backfilling a trench or an old pool. It's what goes underneath — if you're building up a lawn or bed, you fill with fill dirt and then cap the top few inches with topsoil.
How much does fill dirt weigh?
A cubic yard of fill dirt weighs about 1.26 US tons — roughly 1500 kg/m³, or about 94 lb/ft³. Moisture and compaction shift this, so the calculator applies this density and lets you change it in the extra options if your supplier quotes a different figure.
Coverage by depth
| Depth | Coverage per ton | Coverage per cubic yard |
|---|---|---|
| 1 inch | ~256 sq ft | 324 sq ft |
| 2 inches | ~128 sq ft | 162 sq ft |
| 3 inches | ~85 sq ft | 108 sq ft |
| 4 inches | ~64 sq ft | 81 sq ft |
| 6 inches | ~43 sq ft | 54 sq ft |
Based on about 1500 kg/m³. Actual coverage varies with compaction and moisture.
Common mistakes to avoid
- Guessing the depth. Too shallow and the material shifts and shows the ground beneath. Most surface layers want 2–4 inches; load-bearing bases are built up thicker.
- Forgetting to convert inches to feet. Depth is quoted in inches but volume math is in feet — 4 inches is 0.33 ft, not 4. The calculator handles this, but hand estimates often don't.
- Skipping the waste allowance. Ground is never perfectly flat and material settles once it's placed. Order 5–10% extra so a small shortfall doesn't trigger a second delivery.
- Using the wrong density. Each material weighs differently, so tonnage can be off by 20%+ if you use a generic figure. Pick the right material and adjust the density if your supplier differs.
- Buying bags for a big job. Bagged material costs far more per cubic yard than bulk. Past roughly one cubic yard, a bulk delivery is almost always cheaper.
Frequently asked questions
What's the difference between fill dirt and topsoil?+
Fill dirt is subsoil with no organic matter; topsoil is the living top layer that plants grow in. The difference decides your project. Fill dirt is cheap, compacts hard, and doesn't settle further once it's packed — but nothing grows in it. Topsoil grows things, costs more, and keeps decomposing and settling, so using it as bulk fill means paying extra to watch your grade sink. The usual build is fill dirt for the volume, capped with 4–6 inches of topsoil where you want grass or plants.
How much extra fill dirt should I order?+
20–30% more than the calculated volume — not the 10% you'd add for gravel. This is the number people get wrong. Fill dirt is delivered loose and fluffed up, and it packs down hard once it's compacted and rained on, so a yard of loose dirt does not fill a yard of hole. Set the waste field above to 25% for a fill job. Running short mid-project means a second delivery fee on a material that's mostly freight cost anyway.
How much does a yard of fill dirt weigh?+
Roughly 1.25 US tons a cubic yard dry — about 2,500 lb — and considerably more when it's wet, since dirt holds water in a way gravel doesn't. It's sold by the cubic yard rather than the ton for exactly that reason. A half-ton pickup handles about half a yard safely; anything real gets delivered.
Do you have to compact fill dirt?+
Yes, and in layers — this is what separates a fill that lasts from one that sinks. Spread it in 6–8 inch lifts, dampen each lift, and run a plate compactor over it before adding the next. Dumping three feet of dirt in one go leaves air pockets all through it that collapse over the next couple of rainy seasons, and you get a dip exactly where you were trying to raise the ground. Near a foundation this matters even more: settled backfill slopes water back toward the house.
Can you plant grass in fill dirt?+
Not directly — there's no organic matter in it, so grass struggles and weeds win. Fill with fill dirt to get your grade, compact it, then cap with 4–6 inches of topsoil and seed or sod that. Trying to save money by seeding straight into fill dirt usually costs more in the end, because you redo it.