Calculate cut volume, soil weight, truck loads & haul costs for any excavation shape.
Uses the Prismoidal Formula for irregular cross-sections.
Select the shape of your excavation (rectangular, trapezoidal, circular pit, or prismoidal for irregular cuts), enter the dimensions in your preferred unit system, then choose soil type and truck capacity. Hit Calculate Excavation to instantly see bank volume, swelled (loose) volume, truck loads, weight, and estimated haul cost.
Adjust the Swell Factor slider to match your soil conditions — this is the volume increase that happens when soil is disturbed and loosened during excavation.
Getting earthwork volumes right is one of the most financially significant steps in any construction project. Underestimate, and you'll be ordering extra truck hauls mid-project at premium rates. Overestimate, and you're paying workers to move soil you didn't need to. On a typical residential foundation — say a 30 × 40 ft footprint at 5 ft deep — the difference between a 20% and 30% swell factor estimate translates to 22 additional cubic yards of loose material, which at $300/load could mean $660 in unexpected costs.
Civil engineers, site contractors, landscape graders, and pool installers all rely on accurate earthwork calculations before mobilizing equipment. A trench for a utility line uses the trapezoidal formula because of sloped walls required for worker safety. A septic pit is circular. A road cut may need the prismoidal method for accuracy across irregular terrain. This calculator covers all four common scenarios, plus real-world outputs like weight (for weight-restricted haul roads) and fill-back volume (when a portion of the soil is returned for backfill).
The core formulas used:
The prismoidal formula (Simpson's Rule applied to volumes) is the most accurate method for irregular cross-sections and is used in AASHTO standards for roadway earthwork. Bank volume is the in-situ (undisturbed) volume. Loose/swelled volume accounts for the fact that excavated soil expands when disturbed.
Swell factor is the percentage by which excavated soil expands once it's removed from the ground. Compacted earth has air driven out; when excavated, the particles loosen and take up more space. A cubic yard of clay in the ground may become 1.35 cubic yards in a dump truck, directly affecting how many loads you need.
Always use swelled (loose) volume for calculating truck loads, since that's how much physical space the soil occupies in the truck. Bank volume is what you report on your bid as the amount of material to be removed from the ground. Both numbers are shown in the results.
A rectangular cut has perfectly vertical walls — common for machine-cut utility trenches in firm soil or rock. A trapezoidal cut has sloped sides (a wider top than bottom), which is required in softer or cohesionless soils for wall stability and OSHA compliance. Use the trapezoidal tab whenever your walls can't be vertical.
Yes — each shape tab has a unit selector. Choose "Metric (m / m³)" to enter dimensions in meters and get results in cubic meters. Soil density, weight, and haul cost calculations all adapt automatically. Truck capacity input remains in yd³ by convention but you can enter m³ equivalent (1 yd³ ≈ 0.765 m³).