About this calculator
Estimates the take-off for a kerb line: kerb unit count from the line length divided by the unit length, plus the concrete bed and haunch volume that supports it.
Formula
kerbs (incl. waste) = ceil(ceil(line length / unit length) × (1 + waste% / 100))
bed volume = line length × bed width × bed depth
haunch area = 0.5 × haunch width × haunch height (a triangular fillet)
haunch volume = line length × haunch area
total concrete = bed volume + haunch volume
Worked example
Defaults: 20 m kerb line, 500 mm units, 5% waste, 300×100 mm bed, 100×150 mm haunch.
kerbs = ceil(20000/500) = 40; incl. waste = ceil(40 × 1.05) = 42
bed volume = 20000 × 300 × 100 = 600,000,000 mm³ (0.6 m³)
haunch area = 0.5 × 100 × 150 = 7,500 mm²; haunch volume = 20000 × 7,500 = 150,000,000 mm³ (0.15 m³)
total concrete = 750,000,000 mm³ (0.75 m³)
FAQ
Why is the haunch a triangle, not a rectangle? A triangular fillet cast against the back of the kerb is a common haunching profile, but not the only one — if your design uses a different haunch shape, treat this calculator's haunch volume as indicative only and adjust your order accordingly.
Why doesn't the calculator cite a standard?
Kerb unit length, bed size, and haunch size all depend on the kerb product and pavement
design — no standard fixes them, so meta.standards is left empty.
Assumptions and limits
Kerb count is a straight-line count (no corners or curves modelled). The haunch is a simple triangular fillet — a different real haunch shape will need its own volume calculation. Bed and haunch dimensions are disclosed estimates you should adjust to match your own design.