Exterior Paint Calculator Australia — Walls, Fascia, Eaves & Trim
Exterior walls
Perimeter × average wall height. Deduct large windows and doors if significant.
Fascia & eaves (optional)
Eave depth × perimeter. Typical: 450–600 mm eave × house perimeter.
Fascia is typically 190 mm wide — calculator uses 0.19 m² per LM.
Doors & trim (optional)
Each door = approx. 3.5 m² (both sides + frame, 2 coats).
Architraves, reveals, sill mouldings — approx. 0.1 m² per LM.
Exterior paint required
Wall paint
Fascia, eaves & trim paint
Total
This exterior paint calculator estimates litres of paint for all surfaces of an Australian home exterior — walls, eaves, fascia boards, doors, and trim. Coverage rates are set for common Australian exterior surfaces: rendered brick 9 m²/L, weatherboard 12 m²/L, fibre cement (Scyon/Hardiflex) 10 m²/L, and bare or raw substrates lower. Exterior paints typically have a lower spread rate than interior paints due to texture, porosity, and thicker film builds required for UV and weather resistance. The calculator is brand-neutral — always verify the spread rate on your product's data sheet before ordering.
Frequently Asked Questions
What is the best exterior paint for Australian conditions?
Australian conditions — UV intensity, heat cycling, and coastal salt in coastal areas — demand exterior paints with high UV resistance, good elasticity, and mould resistance. Acrylic latex exterior paints are the industry standard, with premium options offering 10–15 year warranties. In bushfire-prone areas, look for products with BAL (Bushfire Attack Level) ratings. For rendered masonry, a breathable acrylic formula prevents moisture trapping under the paint film.
How do I measure exterior wall area?
Measure the external perimeter of the building and multiply by the average wall height from the finished ground level to the eave. For a simple rectangular house: add the four wall lengths and multiply by height. Deduct the area of very large windows, garage doors, and other large openings. Small windows and doors generally don't need deducting when you have a 10% wastage buffer included.
Do I need to prime before painting an exterior?
Yes, for bare or porous surfaces. Bare timber, new fibre cement, unpainted render, and previously unpainted brick all require a primer or sealer coat before topcoating. Priming improves adhesion, reduces paint consumption, and prevents efflorescence (salt deposits) on masonry. Previously painted surfaces in good condition can usually be recoated without primer, after thorough cleaning and sanding of flaking areas.
How often should an Australian home exterior be repainted?
In most Australian climates, a quality exterior repaint lasts 7–12 years depending on surface type, paint quality, and sun exposure. North-facing walls and west-facing walls receive the highest UV load and typically show fading earlier. Coastal homes in salt-air environments should be repainted every 5–8 years. Dark colours fade more visibly than light colours and may need recoating sooner.
What is the coverage difference between interior and exterior paint?
Exterior paints are formulated with a thicker film build for durability and weather resistance, which reduces their spread rate compared to interior paints. A typical exterior acrylic on rendered masonry covers 9–12 m²/L, versus 12–16 m²/L for interior flat paint on smooth plasterboard. Rough or porous exterior surfaces can drop to 6–8 m²/L. Always use the spread rate from the product data sheet, not the label.