About this calculator
Estimates quantities for a monolithic (cast in-situ) concrete wall: concrete volume, double-sided formwork area, and tie count. Quantities only — wall thickness, rebar, and tie spacing must be sized by a qualified engineer against the actual loads.
Formula
net area = wall length × wall height − Σ opening areas
concrete volume (incl. waste) = net area × wall thickness × (1 + waste% / 100)
formwork area (one side) = net area
formwork area (both sides) = 2 × net area
tie columns = ceil(wall length / horizontal tie spacing) + 1
tie rows = ceil(wall height / vertical tie spacing) + 1
ties = tie columns × tie rows
Worked example
Defaults: 6 m × 2.5 m wall, 200 mm thick, one 900×2100 mm door opening, 500 mm tie spacing both directions, 5% waste.
net area = 15,000,000 − 1,890,000 = 13,110,000 mm²
concrete volume = 13,110,000 × 200 × 1.05 = 2,753,100,000 mm³ (≈ 2.75 m³)
formwork both sides = 13,110,000 × 2 = 26,220,000 mm² (≈ 26.22 m²)
ties = (ceil(6000/500)+1) × (ceil(2500/500)+1) = 13 × 6 = 78
FAQ
Does this calculator check whether the wall thickness or tie spacing is adequate? No. This is a quantity take-off only — an info diagnostic reminds you that wall design (thickness, reinforcement, tie spacing and capacity) must be verified by a qualified engineer.
Why are ties counted on a plain grid instead of avoiding the opening? Real tie layout works around openings and formwork panel joints in ways a simple grid does not capture — the grid count here is a usable estimate, not a placement plan.
Why doesn't the calculator cite a standard?
EN 1992-1-1 governs concrete structural design, not a generic formwork/tie quantity take-off,
so meta.standards is left empty.
Assumptions and limits
Ties are counted on a plain grid over the gross wall, not net of openings. This is a quantity take-off only: wall design must be verified by a qualified engineer.