Cut & Fill Calculator

How the Cut and Fill Calculator works

The cut and fill calculator computes earthwork volumes for site grading, road construction, and land development projects. Enter existing and proposed elevations for a grid of survey points to get total cut volume (material to remove), total fill volume (material to import), and the net balance — essential for estimating earthmoving costs and planning haulage logistics.

Average end area method

The most common earthwork calculation method is the average end area (prismoidal) approach: Volume = (A1 + A2)/2 × L, where A1 and A2 are cross-sectional areas at two stations and L is the distance between them. For grids, the four-corner prism method divides the site into rectangular prisms and sums their cut or fill volumes. Both methods are supported by the calculator.

Swell and shrink factors

Earth changes volume when excavated and compacted. Loose clay swells 20–30% when dug, meaning 1 m³ in-situ becomes 1.25 m³ loose. When compacted as fill, the same material shrinks back to 0.85–0.90 m³. The swell factor (for cut haulage trucks) and shrink factor (for fill compaction) are entered as percentages so the calculator gives both bank-measure and compacted-measure volumes.

Net balance and import/export decisions

A negative net balance means more cut than fill — surplus material must be exported. A positive balance requires importing fill material. The cut-fill balance directly determines whether a project is economically self-sustaining or requires additional budget for tipping fees or fill purchase. The tool displays net balance in both loose and compacted cubic metres for contractor pricing.

Application to site grading and road design

Civil engineers use cut-fill analysis to optimise platform levels and road alignments so that cut balances fill, minimising haulage. On road projects, the mass haul diagram derived from cut-fill calculations determines the most efficient direction and distance for moving material between cuttings and embankments, reducing total earthmoving cost significantly.

Frequently asked questions

What is cut and fill in earthworks?

Cut refers to earth that is excavated and removed to lower the ground level toward a design grade. Fill refers to earth that is placed and compacted to raise the ground level. Balancing cut and fill — using cut material as fill elsewhere on the same site — minimises truck haulage costs and avoids the need to import or export material.

What is swell factor?

When soil is excavated from its natural (bank) state, it expands because the particles are loosened. A swell factor of 25% means 1 m³ of in-situ (bank) soil becomes approximately 1.25 m³ when loose. This is important for calculating truck load volumes and the number of trips needed to haul away excavated material.

What is shrinkage factor?

When loose fill material is placed and compacted, it shrinks relative to its loose volume. A shrinkage factor of 10% means 1 m³ of loose fill compacts to approximately 0.9 m³ of compacted fill. This determines how much loose material you need to import to achieve a required compacted fill volume — always order more loose material than the fill volume to account for this.