Grading & Sitework
Earthwork Volume
Earthwork volume calculator using the average end area method for cut/fill volume from cross-section data, with BCY and LCY output.
Earthwork Volume
The average end area method estimates cut or fill volume between two cross-sections by averaging their areas and multiplying by the distance between them. It is the standard method in roadway design for computing earthwork from cross-section data and the typical pay quantity basis under most state DOT specifications.
Cross-section areas are taken at each stationing interval from the ground line and proposed subgrade template. The swell factor converts bank cubic yards (in-situ) to loose cubic yards (excavated). Typical swell: sandy soils 1.10, clays 1.20, rock 1.30–1.40. The prismoidal formula is more exact but requires a mid-section area; average end area is standard for bidding purposes.
V (ft³) = (A₁ + A₂) / 2 × L
V (CY) = V (ft³) / 27
V (LCY) = V (CY) × Swell Factor
Two adjacent cross-sections of 120 ft² and 95 ft², spaced 100 ft apart, average to 107.5 ft², giving 10,750 ft³ (398.1 bank cubic yards) between them. Applying a 1.15 swell factor for typical clay fill converts that to 457.9 loose cubic yards — the volume that actually needs to be hauled and placed, since excavated soil expands beyond its in-situ (bank) volume.
Earthwork Volume Calculator
Average end area — imperial units