Cut and Fill: How Earthwork Balances a Site
Almost every site starts with dirt in the wrong places. Cut and fill is the work of moving it: excavating the high ground, building up the low ground, and getting the pad to design grade. This guide explains how cut and fill quantities are measured, why a yard of cut never equals a yard of fill, what a balanced site means, and how a job ends up importing or exporting dirt when the balance does not hold.
Key takeaways
- Cut is soil excavated from above design grade; fill is soil placed and compacted where the site sits below it. Grading is moving one into the other.
- Earthwork quantities come from comparing the existing surface to the proposed surface, by cross sections, a grid, or a full 3D surface model.
- A yard of cut does not make a yard of fill. Excavated soil swells loose in the truck, then shrinks below its bank volume when compacted to spec.
- A balanced site reuses its own cut as fill so no dirt crosses the gate. Real sites rarely balance on their own; unsuitable material, wet clay, and design changes break the math.
- When the balance fails, the difference is an import order or an export haul, and pricing it early is far cheaper than discovering it mid-grade.
What cut and fill actually means
Take any graded pad, road, or detention pond and compare two surfaces: the ground as it exists and the ground as the plans want it. Everywhere the existing ground sits above design grade, soil has to come out; that volume is cut. Everywhere it sits below, soil has to go in; that volume is fill. The grading plan is the map of both, and the earthwork operation is the sequence of excavating the cut, hauling it across the site, and placing it in the fill zones in compacted lifts until every surface hits grade. On TxDOT work the two halves are literally separate bid items: excavation is Item 110 and embankment is Item 132, each with its own rules for what counts and how it is measured.
How the quantities are measured
Cut and fill volumes are a comparison of surfaces, and there are three standard ways to run it. The cross-section method slices the site at regular stations, measures the cut and fill area on each slice, and averages adjacent sections over the distance between them, the average end area method that road work has used for a century. The grid method lays a square grid over the site, compares existing and proposed elevation at each node, and multiplies the depth difference by the cell area. Modern takeoff software skips the sampling entirely: it builds a triangulated surface model of both the existing ground and the design, subtracts one from the other, and reports cut and fill everywhere at once. That is how our earthwork calculator works, using published LiDAR terrain for the existing surface, and it is why a drone survey or a good topo matters, because the takeoff is only as honest as the existing surface it starts from.
Bank, loose, and compacted: why the yards never match
Every cut-and-fill plan runs through three different cubic yards. Soil measured undisturbed in the ground is a bank yard. Break it loose with a bucket and it swells, taking up more space in the truck as loose yards, commonly on the order of 10 to 25 percent more for common earth and often higher for clay. Compact it into a fill to 95 percent density or better and it shrinks, usually ending up below its original bank volume. So a thousand bank yards of cut hauls like more than a thousand and places like less than a thousand, and a takeoff that treats all three as equal will misorder trucks and misprice the job. The same factors drive ordering the other direction; our guide on how much fill dirt you need walks the import math, and the swell side is covered in the dirt export guide.
The balanced site
A site balances when the cut, after shrink, exactly supplies the fill, so nothing is hauled in or out. Designers chase balance because gate traffic is the expensive part of earthwork: every imported yard is bought twice, once as material and once as trucking, and every exported yard pays for a truck and a place to put it. On paper, raising or lowering the pad a few tenths of a foot swings hundreds of yards from one side of the ledger to the other, which is why grading plans get tuned around the balance point. In practice a perfect balance is rare. Cut that turns out to be organic topsoil, trash fill, or high-plasticity clay cannot go under a building pad, wet material misses density until it dries, and utility trenches and detention ponds generate spoil the plan did not count. The balance survives on some jobs and breaks on most.
When the site does not balance
A site that is short on dirt imports it. What comes in depends on where it lands: select fill under pads and structures, common fill for general grade, each ordered loose with the compaction shrink built into the count. A site that is long on dirt exports it, and the surplus is priced by what it is; clean reusable soil moves cheaper than wet clay or mixed spoil. Either way the fix is a line item, not a crisis, as long as it is known early. The expensive version is finding out at rough grade that the numbers were wrong, when the crew is standing by and material has to move on whatever trucks can be found. Run the takeoff, decide import or export, and lock the material and trucking before the blade hits dirt.
Haul distance: the third number that prices the dirt
Volume says how much moves; haul distance says what moving it costs. Inside the site, dirt that a dozer can push a few hundred feet is cheap, and dirt that needs loading and a wheeled haul costs real money per yard, which is why big grading jobs plan the haul, matching each cut zone to the nearest fill zone and sequencing the work so the dirt moves once. A mass haul diagram is the formal version of that plan, and our earthwork calculator builds one from the takeoff. Once dirt crosses the gate, distance turns into trucking: cycle time to the source pit or the disposal site sets how many loads a truck makes per day, and our guide on dump truck sizes covers what each load carries.
Where the material comes in
The cut-and-fill work belongs to the earthwork crew; the gate traffic is ours. When the balance runs short we deliver the difference, select fill, common fill, or fill dirt to the spec the pad requires, by the truckload across DFW, Austin, San Antonio, and Houston. When it runs long we haul the surplus off and place it. Size the shortfall or the surplus with the earthwork calculator, or send us the grading plan numbers and we will price the material and the trucking together.
Cut and fill FAQ
Running short or long on dirt?
We supply the import and haul off the export: select fill, common fill, and bulk dirt delivered to spec, and surplus removed and placed, across DFW, Austin, San Antonio, and Houston. Send us the takeoff and we price material and trucking together.