Home & DIY calculator
Calculate full tiles and full boxes, not just surface area.
Part of: Flooring & tiling
Tiles = round up[(surface area ÷ tile area) × waste factor]. Boxes = round up(tiles ÷ tiles per box).
A 3 m × 2.5 m surface is 7.5 m². With 30 cm × 30 cm tiles, 10% waste, and 12 tiles per box, buy 8 boxes (96 tiles).
Common questions
Slightly, but for ordering purposes it is common to calculate from tile face area and include a waste allowance.
A common starting point is 10% for a straight or grid layout, 15% for a diagonal layout and 18–20% for herringbone, with about 5% more for large-format tile (tile maker Keope). Some suppliers advise more, for example 20% even for a straight grid (Artistic Tile). Use your installer or supplier figure when you have one.
Multiply the area by (1 + overage %), divide by the area of one tile, round up, then round up again to whole boxes. Example: a 12 ft x 10 ft floor (120 sq ft) with 12 x 12 in tiles needs 120 tiles; with 10% overage that is 132 tiles, with 15% it is 138, and with 20% it is 144. At 10 tiles per box that is 14, 14 and 15 boxes.
The calculator rounds to complete boxes because retailers normally sell tile by the box.