Formwork Area Calculator (m²/ft²)

Compute formwork area by member type and apply opening deduction rules to get net area.

Multipliers are reference values and are not costs (unit price × quantity).

Inputs

Units

Length inputs are unified to mm for metric and in for imperial.

Member type
Shape

Top and bottom end faces are not included (adjust via multipliers or separate items if needed).

Formwork area definition for this member
Surface
Formula
Substitution

Opening deductions (width × height)

Width Height Qty Area Remove

Opening deduction rules

Deduct every opening.
Deduct openings where (width × height) ≥ threshold.
Deduct openings where both width and height ≥ thresholds.
Example: deduct all openings

Multiplier (optional)

Preset
After applying multipliers, values are reference only and not costs.

Results

Formwork area (before deduction)
Opening deductions
Formwork area (after deduction)
After multiplier (reference)
Not a cost
Show breakdown
Member area formulas
Opening-by-opening judgment
Rounding handling

Opening deductions (important)

Deduction conditions (small openings, one-side deductions, thresholds) vary by owner, company, and contract terms.

This tool provides common rule templates. Choose or edit them to match the project.

If uncertain, check the contract, quantity standards, or owner specifications.

This tool is a calculation aid and not a substitute for design, regulations, contracts, or safety requirements.

Preset values are examples and will vary by conditions.