Paint Coverage Calculator
Calculate exactly how many litres of paint you need for any surface — walls, ceilings, exteriors or fences. Handles multiple coats, doors and windows, and different paint spreading rates. Stop over-buying or running short on the job.
🔨 Paint Coverage Calculator
📐 How It Works
Paint coverage depends on the spreading rate of the paint (listed on the tin as m² per litre) and the number of coats. The actual coverage is lower than the theoretical spreading rate due to surface texture, roller nap and application method — add 10% waste. Deduct doors and windows from the gross wall area.
📋 Worked Example
Painting a room: 4 walls averaging 4.5m × 2.7m (two coats, 2 doors, 1 window). Gross area = 4 × 4.5 × 2.7 = 48.6 m². Deductions: 2×1.8 + 1×1.4 = 5.0 m². Net area = 43.6 m². At 12 m²/L × 2 coats: 43.6 ÷ 12 × 2 = 7.27 L. Order 8 L (includes 10% waste).
❓ Frequently Asked Questions
Spreading rates vary by paint type: interior wall paint 10–14 m²/L, exterior paint 8–12 m²/L, ceiling paint 12–16 m²/L, primer 6–10 m²/L. Always use the spreading rate on the tin as the starting point, then add 10% waste for roller application.
New plaster or bare surfaces: 1 coat primer + 2 topcoats minimum. Repainting same colour: 1–2 coats. Colour change (especially lighter to darker or darker to lighter): 2–3 coats. High-traffic areas: always 2 coats of topcoat.
Yes, deduct openings from the gross wall area. Standard door: approximately 1.8 m² (0.9m × 2.0m). Standard window: approximately 1.4 m² (1.0m × 1.4m). For large feature windows or bi-fold doors, measure the actual opening.
Ceiling area = Length × Width of the room. Use ceiling paint spreading rate (12–16 m²/L). Most ceilings need 2 coats for new work, 1 coat for repainting same colour. Add 10% waste.