How the Excavation Calculator works
Volume is length × width × depth, which gives cubic feet. Dividing by 27 converts to cubic yards, the unit excavation and haul-off are quoted in. The tool also reports cubic meters and tonnes for metric work, and you can toggle the whole form between imperial and metric input.
Tonnage is cubic yards multiplied by the material’s density. Six materials are carried, in tons per cubic yard: topsoil at 1.0, common fill dirt at 1.1, sand at 1.3, crushed stone at 1.35, gravel at 1.4, and clay at 1.5. Density is what turns a volume into a truck count, since haul trucks are limited by weight long before they run out of space.
Material cost applies only to the four materials you would normally buy — gravel at $38 a ton, crushed stone at $42, topsoil at $35, and sand at $30. Dirt and clay show no cost, because in most jobs they are spoil you are removing rather than material you are purchasing.
Worked example: a 20 ft by 20 ft footprint dug 4 ft deep is 1,600 cubic feet, or 59.3 cubic yards. As common fill dirt at 1.1 tons per cubic yard that is 65.2 tons to haul. If you were instead bringing that volume in as gravel at 1.4 tons per cubic yard, it would be 83.0 tons and about $3,153 of material.
One caution: these are bank volumes, measured in place. Soil swells when excavated, typically 10% to 30% depending on type, so loose volume in the truck will exceed what is shown here.
Frequently Asked Questions
How many cubic yards are in a cubic foot of excavation?
There are 27 cubic feet in a cubic yard, so you divide cubic feet by 27. A 20 by 20 foot area dug 4 feet deep is 1,600 cubic feet, which is 59.3 cubic yards. Excavation and haul-off are almost always quoted in cubic yards, so this conversion is the first step in every estimate.
How many tons is a cubic yard of dirt?
It depends on the material. The calculator uses 1.1 tons per cubic yard for common fill dirt, 1.0 for topsoil, 1.3 for sand, 1.35 for crushed stone, 1.4 for gravel, and 1.5 for clay. Clay is the heaviest of the six because it holds water and compacts densely, which is why clay haul-off costs more per cubic yard than the same volume of topsoil.
Why does the calculator show no material cost for dirt and clay?
Dirt and clay are priced at zero because they are normally material you are removing, not buying. Gravel, crushed stone, sand, and topsoil carry purchase prices ($38, $42, $30, and $35 per ton respectively) because those are typically brought in. If you are hauling dirt off site, price the trucking and tipping separately from this tool.
Does this account for swell after excavation?
No. The volume shown is bank volume — the material as it sits in the ground. Most soils swell 10% to 30% once broken and loaded, so loose volume in the truck exceeds the figure here. Add a swell factor for your soil type when sizing haul trucks or counting loads.