Formwork Area Calculator
Pick a member type, enter section and length, and get the formwork contact area plus sheet and batten estimates.
Inputs
Result
Formula
| Column | A = 2 × (a + b) × height × qty |
| Beam | A = (width + 2 × depth) × length × qty |
| Slab | A = length × width × qty |
| Wall | A = 2 × length × height × qty |
| Sheets | sheets = A ÷ 2.98 (1220×2440 per sheet) |
One 500 × 500 mm column 3 m tall: 2 × (0.5 + 0.5) = 2 m perimeter, 6.00 m² of contact area, about 3 sheets of plywood — one sheet per set over three reuses. Ten columns give 60 m² and seven sheets per set.
FAQ
Why measure contact area rather than concrete volume?
Formwork is measured, priced and bought by contact area, and there is no fixed ratio to concrete volume. One cubic metre in a massive footing needs almost none, while the same volume in a thin wall needs 8-10 m². Each member must be calculated separately.
Should slab thickness be deducted from beam formwork?
Yes. The side form only runs from the slab soffit down, so its height is beam depth minus slab thickness, and column formwork is reduced by the beam depth at connections. This tool uses the full beam depth, so the result runs slightly high and should be adjusted when cutting.
How do reuse cycles affect cost?
Formwork cost is amortised over reuses: a 100 m² set used three times spreads its price over 300 m², so the rate per square metre is a third of the purchase price. Plywood typically manages 3-5 cycles with edge trimming and release agent, while steel forms reach 20 or more at a higher upfront cost.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.