How to Calculate Fill Dirt
Finished cubic yards = area (sq ft) × fill depth (in) ÷ 324. That is the volume the fill will occupy once it is in place. Loose cubic yards to order = finished cubic yards × (1 + compaction allowance). The allowance is there because dirt that is dumped loose takes up more room than the same dirt after it is spread and compacted.
- Measure the area. Length times width for a rectangle, half of base times height for a triangle, or pi times the radius squared for a circle. For an irregular space, split it into rectangles and add them.
- Decide the fill depth. Measure from the existing ground to the finished grade. If the depth varies, use the average of the shallowest and deepest points.
- Find the finished volume. A 600 sq ft area at 12 inches is 600 × 12 ÷ 324 = 22.22 cubic yards.
- Add the compaction allowance. At 15 percent that is 22.22 × 1.15 = 25.56 cubic yards to order.
- Convert to tons and loads. Multiply the loose yards by the weight of a cubic yard and divide by 2,000, then divide the yards by the truck bed size.
The calculator above does the five steps for rectangles, circles, triangles or a known area, in US or metric units, and shows the weight as a range because fill dirt varies so much from one pit to the next.
Compaction Allowance
Loose dirt is full of air. Once it is spread, rained on and compacted, it packs down, so the pile you order has to be bigger than the layer you want. The presets in the calculator come from three published sources. The Federal Highway Administration says that for moderate soil excavation the shrink ranges from 10 to 25 percent. A Florida DOT study at the University of Central Florida measured seven field projects and found typical shrinkage of 15 to 20 percent. The Iowa Highway Commission defines the shrinkage factor so that fill volume equals excavated volume divided by one plus the factor, which is the relationship the calculator uses in reverse.
| Setting | Allowance | Loose yards per finished yard | Order for the 600 sq ft, 12 in example | Where the figure comes from |
|---|---|---|---|---|
| None | 0% | 1.00 | 22.2 cu yd | No allowance: you only level the dirt and let it settle |
| Light | 10% | 1.10 | 24.4 cu yd | The low end of the FHWA 10 to 25 percent shrink range for moderate soil |
| Typical | 15% | 1.15 | 25.6 cu yd | The low end of the 15 to 20 percent Florida DOT study range |
| High | 25% | 1.25 | 27.8 cu yd | The top of the FHWA range and the 25 percent loose-to-pit figure in the Florida DOT study |
These are highway earthwork numbers, and the FHWA notes they are subject to a variation of plus or minus 33 percent and should give way to field data from similar material when you have it. They also describe a hard case: one cubic yard of earth in the cut can take 1.25 cubic yards in the hauling vehicle and end up as only 0.65 to 0.85 cubic yards in the embankment. That works out to a loose pile of about 1.5 to 1.9 times the finished volume when the dirt is compacted to a highway specification. If you are compacting in layers with a plate compactor or roller, treat High as a floor and add extra in the optional box.
Fill Dirt Quantity Chart
The chart gives finished and loose cubic yards for common areas and fill depths, with the 15 percent Typical allowance. Read the loose figure when you are ordering.
| Area (sq ft) | 3 in: finished / loose (cu yd) | 6 in: finished / loose (cu yd) | 12 in: finished / loose (cu yd) | 24 in: finished / loose (cu yd) |
|---|---|---|---|---|
| 100 | 0.9 / 1.1 | 1.9 / 2.1 | 3.7 / 4.3 | 7.4 / 8.5 |
| 250 | 2.3 / 2.7 | 4.6 / 5.3 | 9.3 / 10.6 | 18.5 / 21.3 |
| 500 | 4.6 / 5.3 | 9.3 / 10.6 | 18.5 / 21.3 | 37.0 / 42.6 |
| 1,000 | 9.3 / 10.6 | 18.5 / 21.3 | 37.0 / 42.6 | 74.1 / 85.2 |
| 2,000 | 18.5 / 21.3 | 37.0 / 42.6 | 74.1 / 85.2 | 148.1 / 170.4 |
For a number that is not in the chart, multiply the finished yards by 1.15, or run it through the tool. To cover a larger yard with a thin layer, the Cubic Yard Calculator also works from square yards and a depth.
Fill Dirt Weight
Fill dirt is sold by the cubic yard in some places and by the ton in others, so you need the weight of a yard to compare quotes. The table shows the loose weights the calculator uses. They are the same figures as the Tons to Cubic Yards Calculator, so the two pages always agree.
| Material | lb per cu yd | Typical lb per cu yd | Tons per cu yd | Cu yd per ton |
|---|---|---|---|---|
| Fill dirt (general dirt) | 2,000 to 3,400 | 2,400 | 1.00 to 1.70 | 0.59 to 1.00 |
| Clay fill | 2,700 to 2,970 | 2,835 | 1.35 to 1.49 | 0.67 to 0.74 |
| Fill sand (dry) | 2,620 to 2,800 | 2,700 | 1.31 to 1.40 | 0.71 to 0.76 |
Dirt uses the 1.0 to 1.7 ton planning range, with 1.2 tons as the baseline, that the Topsoil Calculator and Soil Weight Calculator use; Engineering Toolbox lists loose dry dirt at 76 lb per cubic foot and moist dirt at 78, at the light end of that range. Clay and dry sand are also from Engineering Toolbox, and the Minnesota Stormwater Manual gives clean sand as 1.4 tons per cubic yard. Moisture moves all of these, so use the heavy end after rain.
Truck Loads of Fill Dirt
Truck loads are the loose cubic yards divided by the bed size, rounded up. TxDOT lists single-axle trucks at about 6 cubic yards and tandem-axle beds at usually 12 or 14, and a named rental fleet lists a 16 cubic yard tandem axle rear dump truck. The table rounds up to whole loads.
| Loose cu yd | 6 cu yd truck | 12 cu yd truck | 14 cu yd truck | 16 cu yd truck |
|---|---|---|---|---|
| 5 | 1 | 1 | 1 | 1 |
| 10 | 2 | 1 | 1 | 1 |
| 20 | 4 | 2 | 2 | 2 |
| 30 | 5 | 3 | 3 | 2 |
| 50 | 9 | 5 | 4 | 4 |
| 100 | 17 | 9 | 8 | 7 |
The bed size is a volume, but a truck is also limited by weight. A full 12 yard bed of dirt at the baseline weight is about 14 tons, and about 20 tons at the heavy end of the range. Haulers load to their own limits, so ask how many yards they will put on the truck and enter that as Other in the tool. Delivery charges and minimums are priced separately from the dirt.
Fill Dirt vs Topsoil
The two are not interchangeable. Fill dirt is typically subsoil or excavation spoil dug from below the surface layer, with little organic matter, and it is sold to occupy volume. Topsoil is the biologically active surface layer that plants root in. Use fill dirt to raise a grade, fill a hole or level a pad, then finish with a layer of topsoil wherever you will plant or seed. The Topsoil Calculator sizes that top layer, and our guide to topsoil vs garden soil explains what to ask a supplier for.
Do not fill a planting bed or a lawn entirely with fill dirt. It is often compacted and low in nutrients, and grass and garden plants establish poorly in it. For a raised bed, the Raised Bed Soil Calculator is a better fit.
Fill Dirt Cost
Fill dirt prices vary by region, haul distance and how much the supplier wants to get rid of, so we do not publish a single price per yard. Instead, type the quote you were given into the optional price box in the calculator, per cubic yard or per ton, and it multiplies by the loose yards or the tons. Say your supplier quotes $25 per cubic yard (a made-up figure to show the arithmetic, not a price survey): the 25.6 loose yards in the worked example come to about $639 before delivery.
Delivery is often the larger line on a small order. Ask whether the quote is per yard or per ton, whether the yards are loose or measured after compaction, and whether there is a per-load delivery charge or a minimum. Get two or three quotes, because the same dirt can be free from a construction site that needs to move it and priced by the load at a landscape yard.
Worked Example
Say you are raising a 600 sq ft area (30 by 20 ft) by 12 inches with general fill dirt, and you will tamp it in place.
- Finished volume: 600 × 12 ÷ 324 = 22.22 cubic yards (600 cubic feet).
- Compaction allowance: at 15 percent, 22.22 × 1.15 = 25.56 cubic yards of loose dirt. With no allowance you would order 22.2, and at High (25 percent) 27.8.
- Weight: 25.56 × 2,400 lb ÷ 2,000 = 30.7 tons, with a range of 25.6 to 43.4 tons across the 2,000 to 3,400 lb per cubic yard range.
- Truck loads: 25.56 ÷ 12 = 2.13, which rounds up to 3 loads with a 12 yard truck, or 2 with a 14 yard truck.
So the order is about 26 cubic yards, two or three truck loads depending on the bed, and about 31 tons. Enter the same numbers in the tool above to see the range and the loads.
Common Mistakes
- Ordering the finished volume. The layer you want and the pile you order are different numbers. Without the allowance, a compacted fill ends up several inches low.
- Using the deepest point as the depth. On a slope or a bowl, the deepest spot overstates the fill. Use the average depth, or split the area into sections.
- Mixing loose and compacted yards. A supplier quoting loose yards and a contractor quoting yards in place are not describing the same dirt. Ask which one a quote means.
- Capping the fill with nothing. Where you will plant or seed, finish with topsoil instead of leaving subsoil at the surface.
- Ignoring weight limits. A truck bed that is full by volume can be over its weight limit with wet dirt. Ask the hauler how much they will load.
- Treating the result as exact. The allowance and the weights are planning figures from published sources. Add extra for uneven ground and confirm the numbers with your supplier.
Fill Dirt Calculator FAQ
How much fill dirt do I need?
Multiply the area in square feet by the fill depth in inches and divide by 324 for finished cubic yards, then add the compaction allowance. A 600 sq ft area filled 12 inches deep is 22.2 finished cubic yards, and 25.6 cubic yards to order at 15 percent. The calculator above does both steps and also gives the tons and the truck loads.
Can I use this as a dirt fill calculator for a sloped yard?
Yes, use the average depth. If the fill runs from 2 inches at one end to 10 inches at the other, enter 6 inches. A 20 by 30 ft slope with that average takes 11.1 finished cubic yards before the allowance. For a bowl or an uneven low spot, split it into two or three areas, calculate each at its own depth, and add the results.
Can I use it as a backfill calculator around a foundation or in a trench?
Yes. A trench is a rectangle, so enter its length and width and the depth to be filled. A trench 100 ft long, 2 ft wide and 36 inches deep is 22.2 cubic yards, or 25.6 at 15 percent. Deep backfill is placed and compacted in thin layers, and your engineer or local code sets the layer thickness and the density to reach, so use the High setting or add extra when you compact to a specification.
How much does fill dirt weigh?
Loose fill dirt weighs about 2,000 to 3,400 lb per cubic yard, or 1.0 to 1.7 tons, with 1.2 tons (2,400 lb) as the planning baseline. Clay runs heavier, 2,700 to 2,970 lb, and dry sand about 2,620 to 2,800. Wet dirt weighs more because water adds weight without adding volume, so ask the supplier for their figure.
How much will fill dirt settle, and what compaction allowance should I use?
Highway guidance from the FHWA puts shrink for moderate soil at about 10 to 25 percent, and a Florida DOT study of seven field projects found 15 to 20 percent typical. The calculator offers None, Light (10), Typical (15) and High (25 percent). If you level the dirt and let rain settle it, Light or Typical is reasonable. If you compact it to a specification, go to High or add extra, because the FHWA example has 1 cubic yard of in-ground earth, hauled as 1.25 loose yards, ending up as only 0.65 to 0.85 cubic yards in the embankment.
How many yards of fill dirt does a dump truck hold?
TxDOT lists single-axle trucks at about 6 cubic yards and tandem-axle beds at usually 12 or 14. A 16 cubic yard tandem axle rear dump truck is also offered for rent, in a class that runs 10 to 16. Fill dirt is heavy, so a full 12 yard bed is about 14 tons at the baseline weight, and a hauler may load less than a full bed to stay within the weight limit.
What is the difference between fill dirt and topsoil?
Fill dirt is typically subsoil or excavation spoil with little organic matter, sold to take up volume. Topsoil comes from the surface layer and supports plants. Use fill dirt to raise grade or fill a hole, then cap it with topsoil where you will plant or seed. The Topsoil Calculator sizes that cap layer.
Should I order fill dirt by the yard or by the ton?
Either works if you know which one the supplier is quoting. By the yard, the price covers a volume of loose dirt, and the tons vary with moisture. By the ton, the price covers a weight, and the yards you get vary the same way. The Tons to Cubic Yards Calculator converts a quote either way, using the same 2,000 to 3,400 lb per cubic yard range.
Sources & further reading
The compaction allowance comes from three transportation agency sources: the Federal Highway Administration’s Earthwork Design page (Shrink and Swell Factors), the University of Central Florida report for the Florida Department of Transportation, Investigation of Shrink and Swell Factors for Soils Used in FDOT Construction (Chopra, 1999), and the Iowa State Highway Commission report Shrinkage Factor for Fill Construction (Anderson and Kumar, 1969). Truck bed sizes are from the TxDOT Maintenance Operations Manual page on haul truck size and the Custom Truck One Source listing for a tandem axle 16 cu yd rear dump truck. Dirt, clay and sand densities are from the Engineering Toolbox page Dirt and Mud: Densities, and the clean sand figure is from the Minnesota Stormwater Manual page Material conversions for winter parking lot and sidewalk maintenance. For how we source and check the numbers on every calculator, see our methodology page, and for the full topic see the complete guide to topsoil, garden soil, compost and mulch.
