Wall Paint Calculator Australia — Litres & Tin Sizes
Wall dimensions
Results
Paint required
Suggested tin sizes
Inputs used
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.
How to use this calculator
- Enter wall width and height — measure the wall width in metres and the height from floor to ceiling (typically 2.4 m in standard Australian homes, 2.7 m or 3.0 m in newer builds).
- Enter number of coats — 2 coats is standard for most situations. Use 3 if covering a dark or strong feature colour, or if painting bare or patched plaster.
- Enter spreading rate — the coverage rate for your specific paint in m²/L. Find it on the tin label or the product's Technical Data Sheet (TDS). Common values: 12 m²/L standard interior low sheen; 16 m²/L on smooth previously painted surfaces; 8 m²/L on rough or textured surfaces.
- Read the result — total litres required and the breakdown of tin sizes (1 L, 4 L, 10 L) that add up to your required quantity most efficiently.
Worked example: Feature wall 5.2 m wide × 2.7 m high = 14.04 m². Two coats at 12 m²/L (standard low sheen). Litres required = 14.04 ÷ 12 × 2 = 2.34 L. Buy one 4 L tin — enough with a small surplus for future touch-ups. Using a deep-tinted colour at 10 m²/L, the requirement would be 2.81 L — still within one 4 L tin.
Understanding your results
The calculator returns total litres and a tin breakdown. The key input is the spreading rate — unlike other calculators that use a default, this one lets you enter the exact rate from your paint tin. Using the right figure means you buy exactly what you need rather than over or under-ordering.
Spreading rates on tin labels are typically stated for one coat on a smooth previously painted surface. On rough textures, raw plaster, or after sanding back flaking paint, the actual coverage will be 20–40% lower than the stated rate. If in doubt, buy one additional tin — most Australian hardware stores and paint shops accept returns of unopened, unstirred tins of standard colours.
The tin size breakdown helps minimise waste. Buying the right number of large tins topped up with a small 1 L tin avoids throwing away expensive leftover paint. Leftover paint can be stored in a cool, dry location for 2–5 years if sealed properly — label it with the room name, colour code, and batch number for future touch-ups.
Common mistakes: Using the tin's theoretical coverage without adjusting for surface type, forgetting that the spreading rate applies per coat (multiply by number of coats), and rounding down instead of up when buying tins.
Painting walls in Australia — techniques, products and common issues
Painting a single wall sounds simple, but achieving a smooth, even, professional-quality result requires correct technique, appropriate tools, and an understanding of how Australian conditions affect paint drying and application.
Choosing your tools
For interior walls, a 230 mm or 270 mm roller with a 10–12 mm nap is standard for smooth to lightly textured surfaces. For heavily textured surfaces (sand finish, popcorn ceilings), use a 20–25 mm nap roller to get paint into the texture troughs. A 63 mm or 75 mm angled brush is used for cutting in — painting the edges that the roller can't reach. Use quality roller sleeves — cheap foam rollers leave a stippled finish and can shed fibres into the paint film.
Cutting in and rolling technique
Cut in along the ceiling, skirting and adjacent walls with a brush before rolling. Paint a strip approximately 75–100 mm wide, then immediately roll the main field while the cut-in edges are still wet — this is called "maintaining a wet edge" and prevents a visible lap line where the brush and roller meet. Roll in a W or M pattern to distribute paint evenly, then lightly roll over in one direction to lay off. Work from the unpainted area into the wet paint to avoid streaking.
Drying time between coats
Water-based paint in Australian conditions (20–25°C, moderate humidity) is typically re-coatable in 2–4 hours. In humid coastal conditions or cooler winter temperatures, allow 4–6 hours. Applying a second coat before the first is fully dry can cause the first coat to lift or wrinkle. Touch dry and re-coat dry are different — always check the TDS for the specific re-coat time for your product.
Dealing with common wall problems
Lap marks: Caused by allowing paint to dry before extending the wet edge. Fix by sanding lightly and applying another coat. Roller texture showing through: Paint was applied too thinly or roller nap was too coarse — apply a final thin coat with a fine nap roller. Colour variation between tins: Even same-colour paints can vary between batches. Always mix multiple tins together in a larger bucket before starting ("boxing" the paint) to ensure colour consistency across the wall.
Australian standards and references
- AS/NZS 2311:2017 — Guide to the painting of buildings (application techniques, surface preparation, number of coats, and spreading rate guidance)
- AS/NZS 2310:2002 — Glossary of paint and painting terms (covering spreading rate, wet film thickness, dry film thickness, and re-coat time definitions)
- AS 1580.408.4 — Methods of test for paints — spreading rate (theoretical spreading rate test method for Australian paint products)
- Master Painters Australia (MPA) — Residential painting standards and industry best practice guidelines
- Paint manufacturer Technical Data Sheets (TDS) — Every Australian paint product has a TDS available on the manufacturer's website specifying exact coverage rate, re-coat time, and application conditions