Work out paint quantity instantly with clear inputs, formula shown and shareable results.
Paint quantity is net wall area times coats divided by coverage. Deduct about 1.8 square metres per door or window, and remember that stated coverage assumes a smooth sealed surface — bare plaster or textured walls can consume half again as much on the first coat.
Paint quantity
litres = (wall area - openings) x coats / coverage per litre
Porous or unsealed surfaces absorb paint. A mist coat thinned with water on new plaster seals it and saves topcoat.
It is a best case on a smooth primed surface. Reduce it by 20-30% for textured, dark or previously unpainted walls.