Paint Calculator
Estimate how much paint you need for a room based on its dimensions, number of coats, and paint coverage.
How this is calculated
Wall area = perimeter of the room (2 × (length + width)) × wall height, minus any door/window area you subtract. Paint needed = wall area × number of coats ÷ your paint's coverage rate (how much area one liter covers).
Worked example
A 5m × 4m room with 3m walls has a perimeter-based wall area of 2×(5+4)×3 = 54 sq meters. At 2 coats and a coverage of 10 sq meters per liter, that's 54 × 2 ÷ 10 = 10.8 liters of paint.
Frequently asked questions
Where do I find my paint's coverage rate?
It's usually printed on the paint can label, often as 'covers X square meters/feet per liter/gallon' — use that exact figure for the most accurate estimate.
Does this include the ceiling?
No, this calculates wall area only. If you're painting the ceiling too, add its area (length × width) separately using the same coverage-based method.