Formwork Area Calculator

How is formwork area calculated?

Formwork quantity is the area where the form touches the concrete. For each member you only need to know which faces are formed.

• Column: the four sides are formed. Area = section perimeter × height. For a round column the perimeter is π × diameter.
• Beam: the soffit and the two sides are formed. On a side that meets the slab the form stops at the slab soffit, so the side height is beam depth minus slab thickness. On an edge beam the outer side takes the full depth.
• Slab: the soffit is formed, so the area is length × width. Edge forms on free edges are calculated separately.
• Footing: the sides are formed. Area = base perimeter × depth.
• Wall: both faces are formed. Area = 2 × length × height.

Example

Twelve columns of 30 cm × 60 cm and 3 m high: the perimeter is 2 × (0.30 + 0.60) = 1.8 m, one column takes 1.8 × 3 = 5.4 m² and the total is 64.8 m².

An interior beam of 25 cm × 50 cm on a 12 cm slab, 4.5 m long, has a formed perimeter of 0.25 + 2 × 0.38 = 1.01 m and an area of 4.545 m².

Limits

The tool gives the contact area. Which openings are deducted and how junctions are measured for payment depends on the contract and its measurement rules. When ordering form material, cutting waste and the number of reuses are considered separately.