Shuttering / Formwork Area Calculator
Calculate total shuttering / formwork surface area in m² and ft² for slabs, beams, columns, and footings of any size.
How this works
Each RCC member has a different convention for which faces get shuttered. The calculator applies the conventional field rule per member type:
slab → bottom soffit only: L × W
beam → sides + soffit: (2d + b) × L
column → four vertical faces: 2(b + d) × H
footing → four vertical sides: 2(L + W) × depthBoth square-metre and square-foot figures are reported using the exact conversion factor 1 m² = 10.7639 ft².
Worked example
A 4 m long beam, 230 mm × 450 mm:
(2 × 0.45 + 0.23) × 4 = 1.13 × 4 = 4.52 m²- Equivalent =
4.52 × 10.7639 ≈ 48.65 ft²
Add a 10–15 percent wastage allowance on top of this figure when ordering plywood for the first pour.
Sources
- Conventional South Asian RCC formwork rules (slab soffit only, beam sides + soffit, column / footing four vertical faces).
FAQ
What is shuttering or formwork?
Shuttering (also called formwork) is the temporary mould that holds wet concrete in place until it has cured enough to support its own weight. It is built on site from plywood sheets, steel plates, or aluminium panels supported by props and bracing. The shutter area is the total contact surface between concrete and mould — it drives both the procurement quantity (sheets, props) and the labour cost (carpenter days). Most contractors price shuttering separately from concrete in the BOQ.
Why is the slab shutter only the bottom soffit and not the four sides?
In a typical RCC frame, the slab pours over the beam tops, so the slab edges are formed by the beams themselves. The only shuttering surface for the slab proper is the bottom soffit — the underside that supports the wet concrete. If your slab has a free edge (a cantilever or a parapet drop), add the edge area separately as a thin strip of length × thickness.
Why does the column shutter formula use 2 × (b + d) instead of all six faces?
A column has six faces, but only the four vertical faces are shuttered. The top is open (concrete is poured from above) and the bottom rests on the previously-cast slab or footing. The four vertical faces sum to 2bH + 2dH = 2(b + d) × H. The same logic applies to footing sides — bottom rests on PCC, top is exposed during cure, only the four vertical sides need shuttering.
Why does the beam shutter use (2d + b) × L?
An open beam has two side faces of height d and one bottom soffit of width b. Each side face has area d × L and the soffit has area b × L, summing to (2d + b) × L. The top of the beam is monolithic with the slab, so it does not need a separate shutter. For a beam buried inside a wall (a hidden beam), the side surfaces are formed by the wall masonry and the formwork is only the soffit — divide the result by the relevant fraction.
How do I convert m² to ft² and back?
Use the exact factor 1 m² = 10.7639 ft². So 50 m² = 50 × 10.7639 ≈ 538 ft²; conversely, 1,000 ft² = 1,000 / 10.7639 ≈ 92.9 m². The calculator reports both values automatically. Indian and Nepali contractors typically quote shuttering rates per m² (₹250–600 / m² for plywood) but some legacy quotes use ft² — convert before comparing.
How many times can shuttering plywood be reused?
A 12 mm marine-grade plywood sheet typically reuses 6 to 10 times before the surface and edges deteriorate. After that the shutter face starts pitting the concrete and needs replacement. Steel and aluminium formwork has a much higher reuse count (50+ pours), but the upfront cost is several times higher — only worth it for repetitive projects. Allow 10–15 percent wastage on top of the calculated shutter area for first-pour projects.