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Earthwork Cut & Fill Calculator

Calculate cut and fill volumes for earthwork projects using grid method or cross-section method. Estimate excavation quantities and material balance.

Earthwork & Excavation Site engineers, contractors, quantity surveyors Commercial Intent: HIGH

Engineering Formulas

Grid Method Volume

V = Σ(d × A)
where d = EGL - PFL per grid cell

V: Volume per cell (m³)

d: Depth of cut/fill (m)

A: Grid cell area = d² (m²)

Cross Section Method (Average End Area)

V = ((A₁ + A₂) / 2) × L

V: Volume between sections (m³)

A₁, A₂: Cross-sectional areas (m²)

L: Distance between sections (m)

Borrow / Waste Calculation

Compacted Fill = Fill Vol × CF
Bank Cut = Cut Vol × SF
Borrow = Compacted Fill - Bank Cut

CF: Compaction factor

SF: Swell factor

Worked Example

Site Grading — Grid Method

method: gridgridSize: 10existingLevel: 105proposedLevel: 103area: 1000

Depth

Average cut depth = 105.0 - 103.0 = 2.0 m

Cut Volume

Volume = 2.0 × 1000 = 2,000 m³ (no fill needed)

Swell

Bank cut = 2,000 × 1.25 = 2,500 m³ loose

Haul

Total material to haul: 2,500 m³

Result: Approximately 2,000 m³ of cut (2,500 m³ loose) with no fill required for a 1,000 m² site with 2m average cut depth.

Engineering Notes

Always verify soil types and their corresponding swell/compaction factors with geotechnical reports.

For large projects, create a mass haul diagram to optimize cut-to-fill movements.

Consider weather impacts — wet soils have higher swell factors and may require stabilization.

Retain topsoil (150–300mm) separately for landscaping reuse.

Rock excavation may require blasting or ripping — factor into cost estimates separately.

Assumptions

• Grid method assumes uniform ground between grid points

• Cross-section method assumes linear variation between sections

• Swell and compaction factors are estimates — verify with lab tests

• No differentiation between soil and rock types

• Does not account for topsoil stripping separately

Common Mistakes

✕ Forgetting to apply swell factor to cut volumes for trucking calculations

✕ Using cut volume directly as fill volume without compaction adjustment

✕ Not accounting for topsoil (typically 150–300mm) separate from general cut

✕ Assuming uniform ground conditions across the entire site

✕ Mixing up cut and fill sign conventions

Frequently Asked Questions

What is the difference between cut and fill?

Cut is excavation of material above the desired grade. Fill is placement of material to raise low areas to the desired grade. The goal is to balance cut and fill to minimize hauling.

What is a swell factor?

Swell factor accounts for the increase in volume when soil is excavated. Loose soil occupies more space than in-situ. Typical swell: 25% for common earth, 40% for rock.

What is a compaction factor?

Compaction factor (or shrinkage factor) accounts for the volume reduction when fill is compacted. Typical values: 0.85–0.95 depending on soil type and compaction effort.

Which method should I use — grid or cross-section?

Grid method is best for large, relatively flat areas (sites, parking lots). Cross-section method is better for linear projects (roads, pipelines, canals).

What is a mass haul diagram?

A mass haul diagram plots cumulative cut/fill volume along a project. It helps determine haul distances, borrow requirements, and waste disposal needs.

How do I handle topsoil stripping?

Topsoil (typically 150–300mm) is usually stripped separately and stockpiled for later reuse in landscaping. It should not be mixed with general cut/fill.

What are common causes of earthwork errors?

Common errors include: incorrect swell/compaction factors, not accounting for topsoil stripping, survey errors, and forgetting structural fill below foundations.

How accurate is the grid method?

Accuracy depends on grid size — smaller grids give more accurate results. For preliminary estimates, 20m grids are typical. For detailed design, 5–10m grids are recommended.