Paint Coverage Calculator — Australian Metric
Enter surface area
Enter the total area to be painted. For a full room, use the Room Paint Calculator to get this figure automatically.
Coverage rate is approximate and varies by brand. Check your product data sheet for the exact spread rate.
Paint required
This paint coverage calculator estimates the litres of paint required for any surface area, applying the coverage rate appropriate for the surface type. Australian paint products are rated in square metres per litre (m²/L) on their product data sheets — this calculator uses typical published spread rates: smooth surfaces 16 m²/L, standard rendered or brick surfaces 12 m²/L, rough or porous surfaces 8 m²/L, and highly porous substrates such as bare timber or fibre cement 6 m²/L. The tool is brand-neutral. Always confirm the specific spread rate on your chosen product's data sheet, as coverage varies between brands and formulations.
Frequently Asked Questions
What is a typical paint coverage rate in Australia?
Most interior wall paints sold in Australia cover 12–16 m² per litre on a smooth, previously painted surface at the recommended spread rate. Exterior paints and primers on rough or porous surfaces can drop to 6–10 m²/L. Always check the product data sheet — not the label — for the exact spread rate under your conditions.
How many coats of paint does a room need?
Two coats is standard for a quality finish on previously painted walls in reasonable condition. New plasterboard, bare plaster, or a significant colour change (especially going lighter) will require a sealer or primer plus two topcoats — effectively three coat layers. One coat may be sufficient for a same-colour refresh on a smooth, well-prepared surface.
Why does surface type affect how much paint I need?
Rough and porous surfaces have far more physical area to cover at a microscopic level and absorb more paint into the substrate. A bare brick wall can consume more than twice the paint of smooth plasterboard at the same nominal m² area. Priming porous surfaces before topcoating significantly reduces overall paint consumption.
What can sizes are available in Australia?
Australian paint is commonly sold in 500 mL, 1 L, 2 L, 4 L, 10 L and 15 L containers. Tinted paints are usually mixed in 1 L, 2 L, 4 L, and 10 L sizes. Buying in the largest can size that covers your job reduces cost per litre and minimises colour-match risk between batches.
Should I add extra for touch-ups?
Yes. A 10% buffer is sensible for touch-ups after the job is complete, particularly if you have feature walls, alcoves, or complex cut-in work. Keep a sealed leftover tin in a cool dark place for future touch-ups — label it with the room name, product name, and tint code.