Site Grading & Earthwork Calculators

Calculation Method
Section Areas
For prismoidal method only
Cut/Fill Proportion
Bank-to-loose volume increase
Loose-to-compacted volume decrease
Total Volume (bank measure)
Surplus / Import Material
and t
Cut Volume
Fill Volume
Loose Volume (for transport)
Compacted Fill Volume
Volume Balance Status
Average End Area: V = (A1+A2)/2 × L. Prismoidal: V = L/6 × (A1+4×Am+A2) — more accurate for varying cross-sections. Swell factor accounts for bulking when excavated material is loosened (typically 15–30% depending on soil type). Shrinkage accounts for compaction reducing placed volume (typically 5–15%).
Slope Geometry
Terrace / Bench Layout
Auto from rise/run
Slope Ratio (H:V)
ratio
Angle
°
Terrace Horizontal Spacing
m
Accessibility Classification
Erosion Risk Estimate
Slope % = (rise/run)×100. Ratio H:V = run/rise : 1. Angle = atan(rise/run). General guidance: gradients >1:3 (33%) typically require retaining structures or geotechnical engineering input for stability and erosion control. BS 8004 / Eurocode 7 govern slope stability design for critical slopes.
Feature Type
Cross-Section Geometry
Hydraulics (swale only)
Cross-sectional Area
Top Width
m
Hydraulic Capacity (swale)
L/s
Flow Velocity
m/s
Sediment Trap Length
m
Equivalent Tonnes (berm material)
t
Trapezoidal cross-section: Area = (bottomWidth + sideSlope×depth) × depth. Top width = bottomWidth + 2×sideSlope×depth. Manning’s equation: V = (1/n)×R^(2/3)×S^(1/2), Q = V×A, where R = hydraulic radius = A/wetted perimeter. Target velocity <1.5 m/s to avoid erosion in vegetated channels (CIRIA C753).
Material Properties
Compaction Equipment
Achievable Layer Thickness
mm (for selected equipment)
Estimated Passes Required
passes
Compaction Factor (bank to compacted)
ratio
Target Feasibility Check
Recommend field density verification via: Sand Replacement Test, Nuclear Density Gauge, or Plate Load Test. Proctor test (ASTM D698 / AASHTO T99) establishes MDD and OMC in the laboratory; field compaction should target ≥95% MDD within ±2% of OMC for most landscape sub-base applications.
Material & Volume
Haulage Parameters
Number of Loads
loads
Total Weight
tonnes
Vehicle Trips (round trips)
trips
Total Fuel
litres
Fuel Cost
$ value
Vehicle Hire Cost
$ value
Cost per
$/
CO₂ from Haulage
kg CO₂
Cycle time per load = (2×distance/speed × 60) + loadingTime minutes. Total vehicle hours = loads × cycle time / 60. CO₂ factor: 2.68 kg CO₂ per litre of diesel (DEFRA conversion factors). Consider minimum order quantities and tipping/disposal fees separately — these are not included in this haulage-only estimate.