Paint Calculators Australia
Free paint calculators with Australian coverage rates and metric inputs. Work out exactly how many litres of paint you need for a room, an exterior, a deck or trim — broken down by surface type with suggested can sizes from AU standard paint packaging. No guessing, no wasted paint, no wasted money.
Paint calculators
Paint Coverage Calculator
Enter area, number of coats and surface type to get litres required. Suggests AU standard can sizes.
Open calculator →Room Paint Calculator
Calculate wall paint for a room with dynamic door and window deductions. Ceiling paint option included.
Open calculator →Exterior Paint Calculator
Section-by-section exterior estimate: walls, eaves, fascia, doors and trim — all in one calculation.
Open calculator →Australian paint coverage rates — reference
| Surface type | Coverage rate | Typical application |
|---|---|---|
| Smooth / low porosity | 14–16 m²/L | Gyprock walls, previously painted smooth surfaces |
| Standard / medium porosity | 10–13 m²/L | Standard interior walls, weatherboard, fibre cement |
| Rough / textured | 7–9 m²/L | Masonry, render, Hardiflex, texture-coated surfaces |
| Porous / bare timber | 5–7 m²/L | Raw timber, bare fibre cement, very porous masonry |
Coverage rates are indicative. Always check the manufacturer's stated coverage on the product label as formulations vary. Dulux, Taubmans, Solver and Bristol paints each publish their own spread rates.
Common painting questions for Australian projects
How many litres of paint do I need for a standard Australian house interior?
A typical 4-bedroom house with 240–280 m² of wall area (excluding ceilings) will require approximately 20–30 litres of wall paint for two coats, depending on surface porosity and colour change. Ceilings add another 8–15 litres. Use the room paint calculator for each room and total them up — it's more accurate than a whole-house estimate because room heights and opening counts vary.
What is the standard paint can size in Australia?
Australian hardware stores (Bunnings, Mitre 10, Total Tools) typically stock paint in 500 mL, 1 L, 2 L, 4 L, 10 L and 15 L cans. The 4 L and 10 L sizes offer the best value per litre for large projects. The paint coverage calculator automatically suggests a combination of can sizes to minimise waste.
How many coats of paint does an exterior need in Australia?
Most exterior paints in Australia are specified for two coats on a previously painted surface and three coats on bare or heavily weathered surfaces. In harsh Queensland and Western Australian sun, some manufacturers recommend three coats on all exterior applications for UV durability. Always prime bare timber, bare fibre cement and bare masonry before applying finish coats — the primer coat is not included in coverage rate calculations for finish paint.
What exterior paint coverage rate should I use for a weatherboard house?
Weatherboard (chamferboard) has a moderately high surface area due to the overlapping profile. Use a coverage rate of 10–12 m²/L for the paint area and then add 15–20% extra to the calculated area to account for the recessed back faces and profile edges that are hard to measure. The exterior paint calculator uses 12 m²/L as the default wall rate — adjust it down if you have particularly rough or porous boards.
Do I need a primer before painting in Australia?
Yes, for most bare surfaces: bare plaster/gyprock (use a PVA primer sealer), bare timber (use a wood primer or oil-based primer), bare masonry/render (use a masonry sealer), and bare fibre cement (use a Dulux or Taubmans Prep Coat). Primer coats are not included in finish paint quantities — calculate them separately using the same surface areas but with the primer's spread rate, which is typically lower (around 6–10 m²/L for sealers on porous surfaces).