Standard door ≈ 1.85 m² / 21 sq ft
Standard window ≈ 1.4 m² / 15 sq ft

Paint calculator FAQ

Our calculator uses the standard coverage rate of 10 m² per litre (or 350 sq ft per gallon) and subtracts typical door and window areas. Real-world coverage varies with surface texture, primer, roller nap, and paint brand — expect ±10%. Always buy an extra 10% for touch-ups.

This calculator covers walls only. To estimate ceiling paint, treat the ceiling as a separate room: enter the room's length and width as the "floor area" and ignore height. A flat ceiling typically needs one coat of ceiling paint at the same 10 m²/L coverage rate.

Almost always. A single coat rarely achieves full opacity, especially over a contrasting colour. Premium paints sometimes claim one-coat coverage, but the result usually looks uneven under daylight. Budget for two coats — you can always return unopened tins.

Premium paints use higher-quality resins and pigments — they cover better, resist scrubbing, and last longer in high-traffic areas like hallways and kids' rooms. Economy paint is fine for low-traffic spaces or temporary rentals. For kitchens and bathrooms, choose a premium moisture-resistant formulation.