Paint and Wallpaper Calculator
Enter room dimensions and openings to calculate wall area, paint in litres or gallons and wallpaper rolls.
Measure the room and openings
Enter room length, width, and height. The calculator derives perimeter and gross wall area, then subtracts a standard 1.9 m² per door and 1.4 m² per window.
Paint for multiple coats
Select the number of coats and the coverage printed on the container. For example, 40 m² of net wall area, two coats, and 10 m² per litre produce an 8-litre base need. The result shows 8.8 litres after adding 10% reserve.
Wallpaper strips and pattern repeat
Room perimeter and roll width determine the strip count. Without a repeat, each strip uses room height plus 5 cm. With a repeat, strip length is rounded up to a complete pattern interval. One reserve roll is added.
Check the result before buying
The model does not separately represent unusually large openings, sloped ceilings, alcoves, or accent walls. Always verify opacity, roll length, pattern offset, and surface requirements against the manufacturer specification.