Wall Paint Calculator Australia — Litres & Tin Sizes
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How to calculate wall paint in Australia
To find how much paint you need for a wall, multiply the width by the height to get the area in m², then multiply by the number of coats. Divide by the paint's spreading rate (in m² per litre) to get the total litres required. Australian hardware stores stock paint in 500 mL, 1 L, 2 L, 4 L, 10 L and 15 L tins. The 4 L and 10 L sizes offer the best value per litre. Spreading rates vary by surface porosity — always check the product label from your brand (Dulux, Taubmans, Solver or Bristol) as formulations differ.
Wall paint calculator — FAQs
What spreading rate should I use for interior walls in Australia?
For previously painted plasterboard or Gyprock walls in good condition, use 12–14 m²/L as a starting point. New or bare plasterboard is more porous and may only achieve 8–10 m²/L for the first coat. The manufacturer's stated rate on the tin is always the best reference — it is calculated under standard test conditions and reflects the actual formulation.
How many coats of paint does a wall need in Australia?
Two coats are standard for most interior repaints over a sound existing surface. Three coats are typically needed when: painting over a dark colour with a lighter shade, painting bare plasterboard without a separate primer, or when switching to a dramatically different colour. Some premium paints marketed as "one coat" can achieve adequate coverage in a single application on smooth, non-porous surfaces, but two coats is still recommended for best durability.
What is the standard ceiling height for Australian homes?
Most Australian homes built since the 1980s have 2.4 m ceilings, making the standard wall height for paint calculations 2.4 m. Older homes may have 2.7 m or higher ceilings. New prestige builds often feature 2.7 m or 3.0 m ceilings. Always measure your specific wall height — do not assume 2.4 m without checking.
Do I need to prime a wall before painting in Australia?
Yes, for new or bare surfaces. Bare Gyprock should be sealed with a PVA sealer or paint-and-primer product before applying finish coats — without it, the porous paper face soaks up paint unevenly, leaving a patchy result. Previously painted walls in good condition don't require a separate primer unless you are making a significant colour change (especially dark to light). Use the same spreading rate assumption for primers as for finish coats — sealer primers on bare Gyprock typically cover 6–8 m²/L.
What is the best paint finish for interior walls in Australia?
Low sheen (or "low sheen acrylic") is the most popular interior wall finish in Australia — it resists scuffs and is washable, making it practical for family homes. Flat or matte finishes are used in bedrooms and formal living areas where light reflection is not desired but durability is less critical. Semi-gloss is used on trims, skirtings and doors. High gloss is rarely used on walls in contemporary Australian interiors. In humid areas (bathrooms, laundries) use a paint specifically rated for wet areas.