Paint Coverage Calculator
Calculate exactly how many litres of paint you need for any room or surface, including doors and windows.
Each door subtracts ~1.9m²
Each window subtracts ~1.4m²
Check your paint tin — typically 10–16m²/L
How to Use
1. Measure your room length, width, and ceiling height in metres 2. Count doors and windows (these reduce the paintable area) 3. Check your paint tin for the coverage rate (usually 10–16m²/L) 4. Select number of coats — 2 is standard for colour changesAlways buy slightly more than calculated to account for touch-ups.
Formula
Wall Area = 2 × (L + W) × H − Doors − Windows | Litres = Area × Coats ÷ Coverage × 1.1Frequently Asked Questions
How many coats do I need?
2 coats is standard. Use 3 when painting over a dark colour or on bare plaster. 1 coat may suffice for same-colour touch-ups.
What coverage rate should I use?
Budget paints: 8–10m²/L. Mid-range: 12–14m²/L. Premium: 14–16m²/L. Always check the tin — coverage varies significantly.
Should I buy extra?
Yes — always buy 10–15% more than calculated for touch-ups, mistakes, and second coats that may need more on textured surfaces.
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