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Formwork Area Calculator

Work out formwork area instantly with clear inputs, formula shown and shareable results.

About Formwork Area Calculator

Formwork is measured as the area of concrete surface in contact with the shuttering. A slab contributes its soffit, a downstand beam contributes both sides over its depth below the slab, and columns contribute their full perimeter times height. It is usually the largest labour item in in-situ concrete work.

Formula

Total contact area

Area = slab soffit + 2 x beam length x beam depth + column areas

Worked example

With the default values below, Formwork Area Calculator returns Total formwork area of 157.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Slab soffit areaminimum 0 m²
100 m²
Total beam lengthminimum 0 m
40 m
Beam depth below slabminimum 0 m
0.4 m
Column formwork areaminimum 0 m²
25 m²

Results

Total formwork area
157.00 m²
Slab soffit formwork
100.00 m²
Beam side formwork
32.00 m²
Column formwork
25.00 m²

Step by step

  1. 1Values used
  2. 2Total contact area
  3. 3Total formwork area= 157.00 m²
  4. 4Slab soffit formwork= 100.00 m²
  5. 5Beam side formwork= 32.00 m²
  6. 6Column formwork= 25.00 m²

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Formwork Area figure worked out?

Area = slab soffit + 2 x beam length x beam depth + column areas. Formwork is measured as the area of concrete surface in contact with the shuttering.

Is the beam soffit counted separately?

Only where the beam is wider than the slab opening it frames. Otherwise the soffit strip is normally measured within the slab area to avoid double counting.

What values do I need to enter?

This calculator takes 4 inputs: Slab soffit area, Total beam length, Beam depth below slab, Column formwork area. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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