Estimate formwork contact area, plywood/board sheets and cost — metric or imperial.
This is the concrete-contact surface area of the formwork - it does not include bracing, ties, studs/walers or formwork design.
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Select your structure type - Wall, Column (rectangular or circular), Beam, Slab Edge, Strip Footing, or Pad Footing - and enter its dimensions. Walls let you enter a quantity of identical sections and optionally deduct door/window openings. Slab Edge, Strip Footing and Pad Footing forms let you override the formed length or perimeter if part of the run is against existing ground or structure rather than needing a form. The Area tab calculates formwork contact area automatically. Use the Sheets tab to convert that area into a plywood/board sheet count, and the Cost tab for an itemized material cost estimate.
Formwork contact area is the surface area of formwork that touches the poured concrete. The formula depends on the structure type:
These are standard construction take-off formulas based on the concrete-contact surface only - they don't include the bracing, walers, ties or studs that hold the formwork in place, which are sized separately as part of formwork design. For slab edge, strip footing and pad footing forms, "formed faces" defaults to the full geometric perimeter, but you can enter a custom formed length if only part of it actually needs a form.
The Sheets tab divides your formwork area by the area of one sheet - based on the length and width you enter, defaulting to a standard 2440 × 1220mm sheet - adds a waste allowance, and rounds up. If you know the maximum formwork area required in any single pour, enter it to base your sheet purchase on that figure instead of the full project total; selecting "Sequential reuse" is informational only, since this calculator does not predict how many times a panel can safely be reused. The Cost tab totals your sheet cost plus any optional additional timber/accessories, release agent, labour or other costs you enter - leaving any of these blank simply excludes them from the total.
A 6m × 2.4m wall (formed both faces, quantity 1): area = 2 × 6 × 2.4 = 28.8 m². At three identical sections, total area = 28.8 × 3 = 86.4 m². At 2440 × 1220mm (2.9768 m² per sheet) with 10% waste: area with waste = 31.68 m², needing CEILING(31.68 ÷ 2.9768) = 11 sheets. At $50 per sheet plus $200 labour and $50 other costs: 11 × $50 = $550, plus $200 + $50 = $800 total.
The most common mistake is forgetting that walls need formwork on both faces, not just one - halving the true area needed. Another frequent error is confusing beam formwork (which typically needs two sides plus a soffit/bottom) with wall formwork (two faces only, no bottom) - these are geometrically different shapes. For footings, assuming all faces need a form when part of the run is against undisturbed ground or an existing structure can overstate material needs - the formed-faces override exists for this reason. It's also worth remembering that this calculator estimates contact area only; the bracing, ties and studs that support the formwork against fresh concrete pressure are a separate structural design task, not a simple area take-off.
This calculator estimates formwork contact area (a material take-off quantity) only. It does not calculate fresh concrete pressure, tie/stud/waler spacing, bracing requirements, stripping times, or formwork structural design - these require engineering calculation under a formwork design code (such as ACI 347 or a local equivalent) and should be designed by a qualified engineer, particularly for taller walls, higher pour rates, or loaded formwork. It also does not replicate any specific proprietary formwork system's (e.g. Peri, Doka) panel sizing or load tables, and does not predict how many times formwork can be safely reused.
A poured concrete wall needs formwork on both faces, so area is 2 × wall length × wall height, multiplied by how many identical wall sections you have. You can also deduct door/window openings, and the calculator lets you enter their width, height and quantity. Use the Area tab above with Wall selected.
For a rectangular column, formwork area is the column's perimeter (2 × (side A + side B)) multiplied by its height. For a circular column, it's π × diameter × height. Use the Area tab above with Column selected and choose rectangular or circular.
Beam formwork typically covers two sides and the soffit (bottom), so area is (2 × beam depth + beam width) × beam length. Use the Area tab above with Beam selected.
Slab Edge forms contain the perimeter of a slab pour. Strip Footing forms run along both sides of a continuous footing trench. Pad Footing forms wrap around an individual footing pad. Each has its own dimensions on the Area tab, plus a Formed Faces option letting you enter a custom formed length if part of the perimeter is against existing ground or structure rather than needing a form.
Divide your total (or maximum single-pour) formwork area by the area of one sheet - based on the length and width you enter, defaulting to a standard 2440 × 1220mm sheet - add a waste allowance, then round up. Use the Sheets tab above for an automatic count.
Selecting "Sequential reuse" is informational only and does not change the calculation, since this calculator doesn't predict how many times a panel can be safely reused. If you know the maximum formwork area required in any single pour, enter it on the Sheets tab to base your sheet purchase on that figure instead of the full project total.
No - it calculates formwork contact area (a material take-off quantity) only. Formwork design - including fresh concrete pressure, tie/stud spacing, bracing and stripping time - is a specialist structural engineering task governed by codes like ACI 347 or similar, and must be designed by a qualified engineer.
This calculator estimates general contact area only, which is a useful starting reference regardless of system. It does not use or replicate any specific manufacturer's panel sizing, load tables or system design - refer to your formwork supplier's engineering documentation for system-specific design.