Wall (two faces) + area threshold rule
Input L=6000mm, H=3000mm, faces=2, openings: 900×2100mm×1 / 300×300mm×2, threshold=0.50m²
Output Gross 36.00m², opening deduction 17.82m², net 18.18m²
Formwork Area Calculator (m²/ft²)
Calculate member-based formwork area and choose opening deduction rules to get net area.
Surface definitions and formulas stay visible so project-specific conditions are easier to explain.
Supports Column / Beam / Wall / Slab edge
Opening rules with templates and an explicit edit path
All data is processed locally in your browser
How to use
- Choose unit mode (m² or ft²) and member type.
- Enter member dimensions and quantity, then confirm target surfaces and formula.
- Add opening rows and set deduction faces and deduction rule.
- Review net area and multiplier-based reference value, then copy a share link when needed.
Examples
Beam (side + bottom)
Input B=300mm, D=600mm, L=4500mm, qty=2, end faces off
Output Calculated with side and bottom only, beam top excluded
FAQ
Is the beam top face included?
No by default. Beam calculation targets side faces and bottom face, with end faces as an option.
For wall openings, is deduction one side or both sides?
Default behavior follows member face count automatically. You can override deduction faces when required.
Can small openings be excluded from deduction?
Yes. Use the area-threshold or dimension-threshold template to exclude openings below thresholds.
Is the multiplier result a cost estimate?
No. The multiplier output is a reference area value, not a cost calculation.
Can I save company-specific defaults?
Yes. Use the rule editor to save defaults in this browser.