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Tile Calculator
Work out exactly how many tiles you need.
Paint Calculator
Enter your room dimensions, number of coats, and paint coverage to calculate how many litres or US gallons you need. Supports multiple rooms and both metric and imperial measurements.
How to use the Paint Calculator
Choose litres or gallons
Select your preferred unit at the top. Metric is default; US gallons is available for US users.
Enter room dimensions
For each room, enter the length, width, and ceiling height in metres. Enter the number of doors and windows — these are automatically deducted from the paintable wall area.
Add more rooms (optional)
Click '+ Add room' to include additional rooms in your total. Useful for quoting an entire house repaint.
Set coats and coverage
Choose 1, 2, or 3 coats. Adjust the coverage rate (m² per litre) to match your paint brand — standard emulsions cover 10–12 m²/L.
About this Paint Calculator
Buying the right amount of paint is harder than it looks. Buy too little and you'll run out mid-wall, potentially leaving a visible difference if you need a second batch from a different dye lot. Buy too much and you're wasting money and storing leftover paint that deteriorates over time. The key to an accurate paint estimate is calculating the actual paintable surface area, not just floor area. Our calculator uses wall perimeter × ceiling height to get wall area, then deducts average door sizes (2m²) and window sizes (1.5m²) for a realistic result. Coverage rates vary significantly between paint types. Standard vinyl matt emulsion covers around 12 m² per litre on a smooth surface. Textured or masonry paint may only cover 5–8 m²/L. Specialist primers and undercoats typically cover 8–10 m²/L. Always check the manufacturer's stated coverage on your chosen paint and enter it in the coverage field for the most accurate result. For large colour changes — especially going from a dark to a light colour or vice versa — plan for 3 coats. A freshly plastered wall needs a diluted mist coat first (mix standard emulsion with 10–20% water), followed by two full coats. Our tin options table shows how the number of tins changes across common tin sizes (1L, 2.5L, 5L, 10L) so you can buy the most economical combination.
Frequently Asked Questions
Calculate the total paintable area (wall area minus doors and windows), divide by the paint's coverage rate (typically 10–12 m² per litre), and multiply by the number of coats. Our calculator handles all of this automatically.
Standard emulsion paint covers approximately 10–12 square metres per litre on a smooth surface. High-build or masonry paints may cover less (6–8 m²/L). Check your paint tin for the manufacturer's stated coverage and enter it in our calculator for a more accurate result.
Most surfaces require 2 coats for a quality finish. Going from a light to a dark colour (or vice versa) often requires 3 coats. New plaster or bare surfaces need a diluted mist coat followed by 2 full coats. Our calculator defaults to 2 coats but you can adjust this.
Our paint calculator lets you add ceiling area as a separate room or as part of the overall surface area. Most ceilings use a different paint (typically white matt or ceiling paint), so it's usually best to calculate walls and ceilings separately.