Paint Calculator
Free toolEnter the dimensions of each room, the number of doors and windows, and the number of coats. We calculate the total liters needed and the best can combination to minimize waste.
Result
The area of doors and windows exceeds the wall surface in one room: we set that room to 0 m². Please check the measurements.
Recommended can combination
How to use it
- Enter the length, width and height of the room, and how many doors and windows it has.
- Adjust the number of coats and the paint coverage in square metres per litre, which is printed on the can.
- Add more rooms if you are painting several and read the total litres and the recommended mix of cans.
What it works out and how
Wall area is worked out as perimeter times height, that is 2 × (length + width) × height, minus 1.6 m² per door and 1.5 m² per window. The result is multiplied by the coats (2 by default) and divided by the coverage (10 m² per litre by default). With those litres, the tool looks for the mix of 10, 4, 2.5 and 0.75 litre cans that leaves the least leftover. The ceiling is not included.
Frequently asked questions
How many coats do I need?
Two is normal when repainting in a similar colour. Going from a dark shade to a light one, or painting fresh plaster, calls for a primer or a third coat.
How do I include the ceiling?
The tool only works out walls, so add the ceiling by hand: length times width, multiplied by the coats and divided by the coverage. A 4 × 3 m ceiling with two coats at 10 m² per litre needs 2.4 litres.
Why does my wall use more than the can says?
The coverage on the label assumes smooth, sealed surfaces. Textured walls, unprimed plaster or a long-pile roller can raise consumption noticeably.