Paint, Putty & Knauf
Calculate putty, paint and Knauf drywall system (boards, profiles, screws, Q1-Q3)
How the calculation works
Enter the room dimensions, openings (doors, windows) and whether to include the ceiling. The calculator works out the net wall and ceiling area and from it the amount of putty, paint and, if needed, plasterboard and accessories.
Formula and assumptions
Wall area = perimeter × height − openings; ceiling = length × width. Putty ≈ 1.5 kg/m² (2 coats), 25 kg bags. Paint ≈ 0.125 L/m² per coat × 2 coats = 0.25 L/m², 15 L buckets. Everything is rounded up. Consumption is indicative and depends on the substrate and product.
Worked example
Net area 40 m²: putty 1.5 × 40 = 60 kg → 3 bags × 25 kg = 75 kg. Paint 0.125 × 2 × 40 = 10 L → 1 bucket of 15 L.
What affects real consumption
- Absorbent or uneven walls increase putty and paint use.
- Dark colours and low-opacity paints need an extra coat.
- Application method: roller, brush or spray.
Frequently asked questions
Does the calculator subtract doors and windows?
Yes – enter openings separately and they are subtracted from the wall area.
Why is paint consumption only indicative?
Coverage depends on the product, colour and substrate; use the paint's data sheet for exact figures.