How to Calculate Dirt Needed for Excavation, Backfill, and Truck Loads

Every dirt calculation starts with three distinct volumes: bank cubic yards (BCY), loose cubic yards (LCY), and compacted cubic yards (CCY). If you only calculate one, you will either over-order, under-order, or leave trucks sitting on site. Bank volume is the material in its natural, undisturbed state. Loose volume is what you get after excavation, when the soil has been broken up and aerated. Compacted volume is the final in-place volume after you place and compact it to a specified density.

Here is the relationship that matters on every job:

• BCY to LCY: Multiply by the swell factor. A typical swell factor for common earth is 1.20 to 1.30, meaning 100 BCY becomes 120 to 130 LCY when excavated. Rock can swell 1.40 to 1.60, and sand can swell 1.10 to 1.15.
• BCY to CCY: Multiply by the shrinkage factor. Common earth shrinks to about 0.85 to 0.90 of its bank volume when compacted. That means 100 BCY of undisturbed soil may compact to only 85 to 90 CCY.
• LCY to CCY: Divide the loose volume by the load factor, typically 1.30 to 1.40 for common earth. If you have 130 LCY and a load factor of 1.35, you get about 96 CCY.

These three numbers are not academic. They determine how many trucks you dispatch, how much fill dirt you need to import, and whether your backfill will settle below grade six months after you demobilize. When a contractor asks 'how much dirt do I need,' the correct answer always starts with: for what state, bank, loose, or compacted?

Rule of thumb: Order fill dirt in loose cubic yards, but design and pay for earthwork in compacted cubic yards. The difference is where profit disappears.

If you are sourcing material, NeedsDirt.com lets you search by volume and material type, so you can match your calculated loose volume to available loads instead of guessing. Browse fill dirt listings near you and confirm whether the seller is quoting bank or loose yards before you commit.

The basic formula is always length times width times depth, divided by 27 to convert cubic feet to cubic yards. But contractors rarely work with a single perfect rectangle. Here is a practical workflow that handles the shapes you actually see in the field.

1. Break the site into simple shapes. Divide trenches, building pads, and grading cuts into rectangles, triangles, and trapezoids. Calculate each separately, then add them together. For a trench 120 ft long, 3 ft wide, and 4 ft deep: 120 x 3 x 4 = 1,440 cubic feet. Divide by 27 and you get 53.3 BCY.

2. Apply the swell or shrinkage factor immediately. If that 53.3 BCY is common earth with a 1.25 swell factor, the loose volume you must haul is 66.6 LCY. If the same trench is being backfilled and compacted, the required compacted volume is 53.3 x 0.90 = 48.0 CCY, meaning you need about 48 compacted yards of suitable material, not 53.3.

3. Account for waste and spillage. Add 5 to 10 percent for handling loss, spillage, and over-excavation. On a 48 CCY backfill, a 10 percent waste factor brings you to 52.8 CCY. On small residential jobs, round up to the nearest full load.

4. Use a dirt volume calculator or spreadsheet. Set up columns for length, width, depth, bank volume, swell factor, loose volume, shrinkage factor, compacted volume, and waste. Once built, you can estimate a trench in under two minutes. Many contractors keep a phone calculator app with swell factors pre-loaded by soil type.

5. For building pads, calculate cut and fill separately. A 60 ft by 40 ft pad raised 18 in. requires 60 x 40 x 1.5 = 3,600 cubic feet, or 133.3 CCY. If you are importing fill dirt at a 1.30 load factor, that is about 173 LCY to purchase and haul. If you are cutting the same pad from a high spot, you will generate 133.3 BCY and need to haul away roughly 167 LCY.

When you know your loose volume, you can list or source material on NeedsDirt.com with confidence. Post a dump site if you are exporting, or find fill dirt if you are importing.

Not all dirt behaves the same. The difference between a 10 percent swell and a 30 percent swell on a 500-yard job is 100 loose yards, which can mean three or four extra truckloads. Use the following ranges as planning values, then confirm with a geotech or a sieve analysis on large projects.

• Common earth: Swell 1.20 to 1.30, shrinkage 0.85 to 0.90, load factor 1.30 to 1.40. This is the default for mixed clay, silt, and sand.
• Sand and gravel: Swell 1.10 to 1.15, shrinkage 0.90 to 0.95, load factor 1.10 to 1.20. Sand compacts well and swells less.
• Clay: Swell 1.25 to 1.40, shrinkage 0.80 to 0.90, load factor 1.35 to 1.50. Clay can be tricky because it may compact to a lower density than expected and is sensitive to moisture.
• Rock (blasted): Swell 1.40 to 1.60, shrinkage 0.85 to 1.00 depending on gradation, load factor 1.50 to 1.70. Rock does not shrink much when compacted if it is well graded.
• Topsoil: Swell 1.10 to 1.25, shrinkage 0.80 to 0.90. Topsoil is usually not used as structural fill.

Compaction percent matters more than many contractors admit. A specification calling for 95 percent Standard Proctor density requires more material and more water than 90 percent. If you are backfilling a utility trench under a roadway, expect 95 percent or higher. For landscaped areas, 85 to 90 percent is often acceptable.

Moisture content also changes the math. Wet clay can bulk up and stick in the bed, reducing effective truck capacity. Dry sand can blow off the top, creating a shortage. On a 20-yard truck, a 5 percent loss to spillage or blow-off is a full yard.

Never use a single swell factor across an entire site without checking the soil log. A 10 percent error on a 1,000-yard cut is 100 yards, or roughly $1,500 to $3,000 in hauling and material costs.

When you source fill dirt on NeedsDirt.com, ask the seller for the material type and whether the volume is bank or loose. That one question prevents most volume disputes.

Never calculate truck loads using bank volume. A common mistake is ordering 100 yards and expecting 100 yards to arrive. If the broker quotes bank yards and the truck driver delivers loose yards, the load count will be short. Always specify loose cubic yards when ordering hauled material.

Weight limits also cap loads. A tandem axle is typically limited to about 12 to 14 tons of payload on public roads, depending on axle configuration and local regulations. Dry sand weighs about 1.2 to 1.4 tons per loose cubic yard, so a 14 LCY load could weigh 17 to 20 tons, which is over the limit. Wet clay can weigh 1.4 to 1.6 tons per LCY. In those cases, the truck cubes out on weight before it cubes out on volume. A 20-yard tri-axle may only legally carry 12 to 14 yards of wet clay.

• Material density guide: Topsoil 1.1 to 1.3 tons per LCY, common earth 1.2 to 1.5, clay 1.4 to 1.6, sand 1.2 to 1.4, gravel 1.4 to 1.7, crushed stone 1.4 to 1.8.
• Load count formula: Total LCY divided by truck capacity in LCY, then round up. Add one load for site access issues and spillage.
• Cycle time matters: If the round trip is 45 minutes and you have a 10-hour day, one truck can make about 13 trips. To move 125 LCY with 14-yard trucks, you need 9 loads, which one truck can handle in a day if the site is ready.

If you are exporting material, list your dump site on NeedsDirt.com and specify the material type and estimated loose volume. If you are importing, browse fill dirt near you and confirm truck capacity and access before you schedule deliveries.

Excavation volume is what you remove. Backfill volume is what you put back. They are rarely the same number, and treating them as equal is one of the most expensive mistakes in earthwork.

Suppose you dig a foundation trench 80 ft long, 4 ft wide, and 6 ft deep. The bank volume is 80 x 4 x 6 = 1,920 cubic feet, or 71.1 BCY. The loose volume you haul away is 71.1 x 1.25 = 88.9 LCY, about 7 tandem loads.

Now suppose you backfill the same trench around a foundation wall that occupies 20 percent of the volume. The volume to fill is 71.1 x 0.80 = 56.9 BCY. But you need compacted volume, so divide by the shrinkage factor. If the shrinkage factor is 0.90, you need 56.9 / 0.90 = 63.2 CCY of suitable material. If you are importing fill dirt, that is 63.2 x 1.30 = 82.2 LCY to purchase and haul.

Notice the gap: you removed 88.9 LCY and you need 82.2 LCY to replace, but the numbers do not offset because the excavated material may not be suitable for structural backfill. If the native soil is expansive clay or organic silt, you may need to export all 88.9 LCY and import 82.2 LCY of select fill. That is a significant cost difference.

Always separate your estimate into three lines: unsuitable export, suitable on-site reuse, and import requirement. Never assume excavated material can be reused as backfill without testing or visual classification.

For building pads, the same logic applies. If you cut 500 BCY and fill 500 BCY, you are not balanced unless the cut material meets the fill specification and the shrinkage is accounted for. A 10 percent shrinkage on 500 BCY means you need 555 BCY of bank cut to produce 500 CCY of fill. That 55-yard gap must come from somewhere, either a borrow area or an import.

NeedsDirt.com is built for this reality. Contractors can list surplus excavation material as a dump site and source select fill dirt for backfill in the same marketplace, turning a disposal problem into a cost offset.

Here are three worked examples you can adapt to your next bid.

Example 1: Utility trench. Trench is 200 ft long, 2.5 ft wide, and 5 ft deep. Bank volume: 200 x 2.5 x 5 = 2,500 cubic feet / 27 = 92.6 BCY. Swell factor 1.25 gives 115.8 LCY to export. At 14 LCY per tandem, that is 9 loads. If you backfill with the same material and compact to 90 percent, required compacted volume is 92.6 x 0.90 = 83.3 CCY. With a 10 percent waste factor, order 91.7 CCY. If importing at a 1.30 load factor, that is 119.2 LCY, or 9 tri-axle loads at 14 LCY each.

Example 2: Building pad. Pad is 100 ft by 60 ft, raised 2 ft. Compacted fill volume: 100 x 60 x 2 = 12,000 cubic feet / 27 = 444.4 CCY. Shrinkage factor 0.90 means you need 444.4 / 0.90 = 493.8 BCY of borrow. Loose volume to import is 493.8 x 1.30 = 642 LCY. At 18 LCY per tri-axle, that is 36 loads. Add 5 percent waste and round up to 38 loads.

Example 3: Grading cut. You are cutting a 150 ft by 80 ft area by an average of 1.5 ft. Bank volume: 150 x 80 x 1.5 = 18,000 cubic feet / 27 = 666.7 BCY. Loose volume: 666.7 x 1.25 = 833.4 LCY. At 20 LCY per semi end-dump, that is 42 loads. If the material is suitable for reuse on another part of the site, you can reduce both export and import. If not, you need a dump site for 833 LCY and a borrow source for any fill.

• Cost benchmarks: Fill dirt typically costs $10 to $30 per cubic yard delivered, depending on region and material. Dump fees range from $5 to $25 per cubic yard. Trucking can add $5 to $15 per yard for a 10-mile haul.
• Time benchmarks: A tri-axle can move about 150 to 200 LCY per day on a short haul. A tandem can move 100 to 140 LCY.
• Bid cushion: Add 10 percent to your volume and 15 percent to your trucking time on urban sites with limited access.

When your numbers are ready, find fill dirt or list a dump site on NeedsDirt.com to lock in material and hauling before you mobilize.

Even experienced estimators make these errors. Check your next takeoff against this list.

• Using bank volume for truck counts. Always convert to loose cubic yards before dividing by truck capacity. A 20 percent swell on a 500-yard cut is 100 extra yards, or five to seven extra loads.
• Ignoring shrinkage on backfill. If you order the same volume you excavated, you will be short after compaction. Apply the shrinkage factor and add waste.
• Forgetting unsuitable material. Organic silt, expansive clay, and debris cannot be used as structural fill. Assume a percentage of your cut is unsuitable and plan for export and import.
• Overlooking moisture and density. Wet clay is heavy and may exceed axle limits. Dry sand may blow off. Adjust load counts for actual conditions.
• Not accounting for over-excavation. Trenches and footings are often dug wider or deeper than plan. A 6 in. over-dig on a 200 ft trench can add 5 to 10 yards.
• Using one swell factor for the whole site. Soil changes with depth. A single bore log may not represent the entire cut.
• Forgetting access and cycle time. A narrow driveway or low overhead wire can slow trucks and reduce daily production by 20 to 30 percent.

Build a checklist into your estimating template: bank volume, swell factor, loose volume, shrinkage factor, compacted volume, waste factor, unsuitable percentage, truck capacity, load count, cycle time, and cost per yard. That checklist turns a guess into a defensible number.

If your dirt estimate does not include swell, shrinkage, waste, and truck capacity, it is not an estimate. It is a hope.

NeedsDirt.com helps contractors verify market availability and pricing before they commit to a bid. Search fill dirt listings, compare dump sites, and confirm haul distances so your estimate reflects real logistics, not idealized assumptions.

Once you know how much dirt you need, the next step is sourcing or disposing of it efficiently. NeedsDirt.com is a marketplace built for contractors who need fill dirt, dump sites, and excavation material without the usual phone tag and broker markups.

Here is how to use your calculation on the platform:

• If you are importing fill: Convert your compacted volume to loose cubic yards using the load factor, add waste, and search for fill dirt listings that match your volume and material type. Confirm whether the seller quotes bank or loose yards.
• If you are exporting material: Calculate your loose volume using the swell factor and list your site as a dump site. Specify material type, estimated LCY, access restrictions, and any dumping fees. Contractors looking for clean fill will find you.
• If you are balancing on site: Calculate cut and fill separately, apply shrinkage, and determine whether you have a surplus or deficit. List the surplus as a dump site and source the deficit as fill dirt.
• If you need select material: Use material filters to find sand, gravel, topsoil, or engineered fill that meets your compaction specification.

Your dirt volume calculator gives you the number. NeedsDirt.com gives you the network to move it. Whether you are digging a single utility trench or grading a 50-acre subdivision, the same discipline applies: calculate bank, loose, and compacted volumes, apply swell and shrinkage, account for waste and truck capacity, and source or list material through a marketplace that understands earthwork.

Bookmark your calculations, keep your swell and shrinkage factors by soil type, and always confirm volumes in writing before trucks roll. That is how you protect your margin on every dirt job.