CalcCalculatrice de Peinture
Dernière mise à jour: 2026-05-07
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| Longueur du mur (m) | Hauteur du mur (m) | Nombre de couches (pcs) | Type de peinture | Surface portes et fenêtres (pcs) |
|---|---|---|---|---|
| 10 m | 2.5 m | 2 pcs | 1 | 2 pcs |
| 12 m | 2.5 m | 2 pcs | 1 | 3 pcs |
| 14 m | 2.7 m | 2 pcs | 1 | 3 pcs |
| 16 m | 2.7 m | 2 pcs | 1 | 4 pcs |
| 20 m | 3 m | 3 pcs | 1 | 4 pcs |
What is the Paint Coverage Calculator?
A common DIY mistake is buying paint by guessing — either running short halfway through the second coat or ending up with cans you'll never use. This calculator measures the paintable wall area, subtracts doors and windows, and divides by your paint's coverage rate per litre to give you an exact purchase quantity by number of coats.
You may also find the Wallpaper Calculator, Backsplash Tile Calculator, and Crown Molding Calculator useful.
Who Uses This Calculator?
This tool is used by homeowners painting a room, professional painters quoting jobs, and property managers budgeting for interior refreshes.
How to Use the Paint Coverage Calculator
- Enter your Wall length.
- Enter your Wall height.
- Enter your Number of coats.
- Enter your Paint type.
- Enter your Doors & windows area.
- Click Calculate to see your results instantly.
Formula
The calculator uses the following formula:
Paintable area = (perimeter × height) - doors_windows; Litres = area × coats ÷ coverage_per_litre
Worked Example
A 5 m × 4 m room with 2.7 m ceilings, 2 coats, one door, and two windows has about 43 m² of paintable surface. At 12 m²/litre coverage: 3.6 litres needed, so buy two 2-litre tins.
Step-by-Step Calculation
- Total wall area: 4 × 14 m × 2.5 m = 140 m² (for a square room — adjust for actual perimeter)
- Subtract doors/windows: 3 × 2 m² = 6 m² → 134 m² paintable
- Standard paint: 10-12 m²/litre; 2 coats: 134 × 2 ÷ 11 = 24.4 litres
- 5L cans: ceil(24.4 ÷ 5) = 5 cans
Common Mistakes to Avoid
- Using the floor area instead of the wall area
- Forgetting that dark colours or stained walls need 3 coats instead of 2
- Not accounting for texture — rough or porous walls absorb 20-30% more paint
Frequently Asked Questions
Most interior wall paints cover 10–14 m² per litre per coat. Quality paints are often at the higher end (13–16 m²/L). Exterior paints cover 8–12 m²/L. Primers typically cover 8–12 m²/L. Always check your specific product's data sheet.
Yes — a standard door is about 1.8 m² and a window 1.5 m². This calculator lets you enter the number of each and deducts them automatically. Skipping this step overestimates paint by 10–20% in a typical room.
Two coats are standard for most interior repaint jobs. New plasterboard or a drastic colour change may need 3 coats. One coat is sufficient only for touch-ups or very similar colour-on-colour.
Always paint the ceiling first, then walls from top to bottom. This way any drips or spatters on the wall get covered when you paint the wall. Paint skirting boards last.
For a triangular vault, add (0.5 × width × height of triangle) to the rectangular wall area below. For a curved vault, measure the arc length and multiply by the room length.