Putty and Paint Consumption per m²: How Much for a Wall
How much putty and paint do you need for a room or a 50 m² wall? The calculator uses 1.5 kg of putty per m² (two coats) and 0.125 l of paint per m² per coat.
Step 1: Net wall area
Area = perimeter × height − doors and windows. Room 4 × 5 m, height 2.6 m: perimeter 18 m × 2.6 = 46.8 m²; minus a door (2 m²) and a window (1.5 m²) = 43.3 m². Add the ceiling (4 × 5 = 20 m²) if you paint it.
Step 2: Putty consumption
The calculator uses 1.5 kg/m² for two coats of putty. A 50 m² wall: 50 × 1.5 = 75 kg = 3 bags of 25 kg. A 40 m² wall: 60 kg, so 3 bags (75 kg).
Step 3: Paint consumption
0.125 l/m² per coat, so 0.25 l/m² for two coats. 50 m² needs 12.5 l, which is one 15 l bucket. 80 m² needs 20 l, so two buckets (30 l).
Quick table by area
Putty 1.5 kg/m² in 25 kg bags; paint 0.25 l/m² (two coats) in 15 l buckets. Quantities are rounded up.
| Area (m²) | Putty (kg) | Putty bags (25 kg) | Paint (l) | Paint buckets (15 l) |
|---|---|---|---|---|
| 10 | 15 | 1 | 2.5 | 1 |
| 20 | 30 | 2 | 5 | 1 |
| 30 | 45 | 2 | 7.5 | 1 |
| 40 | 60 | 3 | 10 | 1 |
| 50 | 75 | 3 | 12.5 | 1 |
| 80 | 120 | 5 | 20 | 2 |
| 100 | 150 | 6 | 25 | 2 |
What changes consumption
- Absorbent or uneven walls need more putty and paint.
- Dark colours and low-opacity paint may need a third coat.
- Roller, brush or spray give different consumption.
- Primer reduces how much paint the wall absorbs.
Common mistakes
- Not subtracting windows and doors, or forgetting the ceiling.
- Painting over fresh putty without primer, which soaks up paint.
- Buying exactly the calculated amount: add 5–10 %.
- Using these figures for thick levelling: 1.5 kg/m² is for thin finishing coats.
- Mixing paint from different batches on one wall: buy it all at once.
Frequently asked questions
How much putty for 50 m² of wall?
About 75 kg, which is three 25 kg bags (1.5 kg/m² for two coats).
How many litres of paint for 50 m²?
12.5 l for two coats (0.125 l/m² per coat), so one 15 l bucket.
Is consumption the same for all products?
No. These are indicative values; the exact figures are on the product data sheet.
Open the calculator: Paint, Putty & Knauf