Enter the area you plan to cover and it estimates how many tiles or how much paint you need in advance. It factors in waste rate and number of coats so you buy enough without overspending.

Area = width x height. Tiles = ceil(area x (1 + waste rate) / area of one tile). Paint = area x coats / coverage (m2/L); cans = ceil(paint / can size).

For a 3 m x 2.4 m (7.2 m2) wall with 30x30 cm tiles at a 10% waste rate, you need about 88 tiles. Painting the same wall twice with paint that covers 10 m2/L uses about 1.44 L.