Wall Putty Calculator
Updated
Wall putty is the white-cement layer that smooths plaster before painting — this calculator turns your wall area into kilograms and bags. Enter the area and the coverage from the bag, and it gives the putty required. Coverage is product-dependent, so it is an input, not an assumption.
Wall Putty Calculator
Putty in kilograms and bags for any wall area
Length × height of the walls to be puttied.
Two coats — product-dependent, ~0.4–0.6 kg/m². Check the bag.
Wall putty required
50 kg
100 m² at 0.5 kg/m² · 2 bags of 40 kg
Putty (kg)
50
Bags (40 kg)
2
Coverage
0.5 kg/m²
Area
100 m²
Putty coverage depends on the product and surface — white-cement putties typically give two coats at around 0.4–0.6 kg/m²; always check the bag. Apply putty on primed, cured plaster, then paint. Work out the paint on the paint calculator and see the paint choices in types of paint.
~0.4–0.6 kg/m²
Typical two-coat coverage
Area × coverage
The quantity
Putty → primer → paint
The order
How the calculation works
Putty (kg) = Wall area (m²) × Coverage (kg/m²) Bags = Putty ÷ Bag size (rounded up)
For 100 m² of wall at a coverage of 0.5 kg/m² (two coats):
- Putty = 100 × 0.5 = 50 kg
- Bags = 50 ÷ 40 = 2 bags of 40 kg (rounded up)
White-cement wall putties typically cover about 0.4–0.6 kg/m² for two coats, but this varies with the product, the surface and the coats — always check the figure printed on the bag.
Where putty fits in the sequence
Putty goes on cured plaster, after any cracks are filled, and is rubbed smooth between coats. Then primer, then paint:
- Plaster and let it cure.
- Two coats of wall putty, sanded smooth.
- Primer.
- Two coats of paint.
Putty gives the smooth, hard base that makes emulsion paint look even and last — see the finishes in types of paint. Work out the plaster first with the plaster calculator.
Frequently asked questions
How much putty is needed for 100 square meters? At a typical two-coat coverage of 0.5 kg/m², 100 m² needs about 50 kg of putty — two 40 kg bags. Confirm the coverage on your product, as it varies.
How do I calculate wall putty quantity? Multiply the wall area in square metres by the coverage in kg/m² from the bag. For example, 100 m² × 0.5 kg/m² = 50 kg.
What is the coverage of wall putty per kg? White-cement putties commonly cover around 1.6–2.5 m² per kg for two coats (about 0.4–0.6 kg/m²), depending on the brand and surface. Always check the bag.
Do I apply putty before or after primer? Putty goes on first, directly over cured plaster, and is sanded smooth. Primer follows the putty, and then the paint.
Can I skip wall putty? You can paint straight onto plaster, but putty gives a much smoother, harder base, so the paint looks even and lasts longer. It is standard for a good interior finish.
CivilSite Editorial Team✓ Engineer reviewed
Written and reviewed by practising civil engineers with 10+ years of Indian residential construction experience.