Paint Calculator
Estimate how much paint you need to cover the walls of a room.
Results update as you type.
About this calculator
A paint calculator estimates how much paint a room needs from its dimensions and the number of coats. It works out the wall area (the perimeter times the height), subtracts doors and windows, multiplies by the coats, and divides by the paint’s coverage to give the litres or gallons to buy.
Frequently asked questions
How much paint do I need per square metre?
One litre of wall paint typically covers about 10–12 m² (a US gallon covers roughly 350 sq ft) in a single coat. This calculator assumes 10 m²/litre or 350 sq ft/gallon unless you override the coverage.
Should I paint two coats?
Usually yes. Two coats give an even colour and better durability, especially over a new or contrasting surface, which is why the calculator defaults to two and doubles the paint accordingly.
Should I paint two coats?
Usually yes. Two coats give an even colour and better durability, especially over a new or contrasting surface, which is why the calculator defaults to two and doubles the paint accordingly.
Results are estimates for general guidance only, not financial, medical or tax advice.