About the Paint Calculator
Measure the room, choose the number of coats and doors and windows, and get the amount of paint to buy — with a suggested combination of tin sizes.
How does the Paint Calculator work?
Wall area is the room’s perimeter times the wall height, minus about 1.9 m² for each door and 1.5 m² for each window. That area times the number of coats, divided by the paint’s coverage, gives the paint needed.
Paint Calculator formula
paint = (2 × (length + width) × height − openings) × coats ÷ coverage