How do I use the Paint Calculator?
Enter your values in the fields and the result updates instantly as you type.
Paint Calculator
Calculate how much paint you need for walls and ceilings. Enter your values, review the formula, and use the worked result as a quick check for everyday planning.
Paint Calculator
Calculate how much paint you need for walls and ceilings.
Length of the room
Width of the room
Height of walls
Standard door = 2m²
Standard window = 1.5m²
Usually 2 coats needed
Results
Wall Area
31.5 m²
Ceiling Area
12 m²
Total Area to Paint
43.5 m²
Paint Needed
8.7 L
Cans (4L)
3 cans
Formula: Paint (L) = (Wall Area + Ceiling Area) / Coverage per Liter
Paint Calculator: How Much Paint Do You Need?
Estimate how many liters of paint you need for a room, including walls and ceiling, minus doors and windows. Specify the number of coats for a complete estimate including standard can sizes.
Formula
Wall Area = 2 × (Length + Width) × Height. Ceiling Area = Length × Width. Deduct door area (2 m² each) and window area (1.5 m² each). Total Paint = (Total Area × Coats) ÷ 10 (coverage: 10 m²/L per coat).
Worked example
A 4 m × 3 m room with 2.5 m walls, 1 door, 1 window, 2 coats: wall area is 35 m² (minus 3.5 m² openings = 31.5 m²), ceiling is 12 m², total 43.5 m². Paint needed: about 8.7 L. Cans: 3 × 4L cans.
Practical guidance
Coverage varies by surface and color
The standard estimate of 10 m² per liter per coat assumes smooth, primed walls. Rough or porous surfaces, dark-to-light color changes, and textured walls consume more paint. Add 20% extra for safety on first-time projects.
Primer vs topcoat
This calculator estimates topcoat paint only. If you need primer (recommended for new drywall, stained areas, or drastic color changes), add a separate primer calculation. Primer usually covers more area per liter than topcoat.
Frequently asked questions
What formula does this calculator use?
Paint (L) = (Wall Area + Ceiling Area) / Coverage per Liter
Can I use decimal values?
Yes. Decimal inputs are supported for most calculators. Integer-based tools use rounded integer values where appropriate.
Is this calculator free?
Yes. CalcuNimble calculators are free and optimized for fast everyday use.