Formwork / Plywood quantity
Formwork Plywood Calculator
Estimate whole plywood sheets from formwork contact area, sheet dimensions, deductions, and a waste allowance.
Estimate plywood sheets
Enter the formwork contact area, deductions, sheet size, and planning allowance.
Formwork area
The total plywood surface expected to touch the concrete.
Enter 0 if there are no openings to deduct.
Plywood sheet
Presets are conveniences; use the dimensions supplied by your manufacturer.
Use 0% to 50%. The default planning allowance is 10%.
Plywood to procure
- Whole sheets
- 34 sheets
- Fractional requirement
- 33.2572 sheets
Area breakdown
- Net contact area
- 90 m²
- Waste area
- 9 m²
- Adjusted area
- 99 m²
- Coverage per sheet
- 2.9768 m²
- Purchased area
- 101.2112 m²
- Nominal excess area
- 2.2112 m²
Method
How the plywood estimate works
Start with the gross surface area that will contact the concrete. Subtract openings, add your chosen waste allowance, and divide the adjusted area by the usable area of one plywood sheet. The final procurement quantity rounds upward to a whole sheet.
- Net contact area = gross contact area − opening deductions
- Adjusted area = net contact area × (1 + waste allowance ÷ 100)
- Sheet area = sheet length × sheet width
- Whole sheets = adjusted area ÷ sheet area, rounded upward
Worked example
Example: 100 m² of gross formwork
For 100 m² gross contact area, 10 m² of openings, 1220 × 2440 mm sheets, and 10% waste, the net area is 90 m² and the adjusted area is 99 m². Each sheet covers 2.9768 m², giving about 33.2572 fractional sheets. Round upward to procure 34 sheets.
Scope
Assumptions and limitations
- The contact area is supplied by you; this version does not calculate slab, wall, beam, or column geometry.
- Sheet presets are convenient starting points. Confirm the dimensions available from your supplier.
- The estimate treats each sheet as fully usable rectangular area.
- It does not optimize cuts or account for saw kerf, grain direction, reusable offcuts, or panel reuse between pours.
- It does not size structural formwork components or check local construction requirements.
Common questions
Formwork plywood calculator FAQ
What is formwork contact area?
It is the surface area of plywood expected to touch the fresh concrete. Only faces that require plywood formwork should be included.
Why does the calculator round up?
Plywood is normally procured as whole sheets. A fractional requirement therefore needs the next whole sheet before any supplier pack rules are considered.
Are 1220 × 2440 mm and 4 × 8 ft the same sheet?
They are close but not physically identical. The presets remain separate, and switching units preserves the dimensions currently entered rather than silently selecting another preset.
Does the result include plywood reuse?
No. Reuse depends on pour sequence, stripping damage, panel layout, finish requirements, and site practice. This first version estimates sheets for one stated contact-area requirement.