Construction & estimating · Concrete & reinforcement

Formwork contact area calculator

Formwork area for slabs, beams, columns and footing edges, ply sheets allowing for re-use, and cost.

Standard: Contact area by element · ply sheets with re-use

Inputs in the worked example

The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.

Diagram for the worked example

Beams: L × (2D + b); columns: 2(b + d)·H per column
Rates are example inputs only. Replace them with current supplier quotes and local labour rates.

Concrete materials estimate — Cement bags, sand, aggregate and water for site-mixed concrete by ratio, with wastage.
Bar schedule & rebar weight — Reinforcement mass by bar mark, totals by diameter and tonnage to order.
Concrete volumes & cost — Volumes for footings, slabs, beams and columns, order quantity rounded to 0.2 m³, trucks and cost.
Reinforcement quantities & cost — Steel tonnage from a kg/m³ ratio or a bar list, with laps and waste, supply and fix cost.
Earthworks cut & fill — Volumes from cross-section areas, loose and compacted volumes, truck loads and a mass-haul diagram.
Excavation, cart-away & disposal — Excavated bank volume with batters, bulking, backfill retained, truck loads, tonnes to tip and cost.

For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.