How this calculation works
Tile dimensions are converted from centimetres to metres before calculating area. The count is rounded up after applying the allowance. This is an area-based estimate, not a layout plan.
Tile count = ceiling(area ÷ tile area × (1 + allowance/100))A worked example
For 10 m² using 50 × 50 cm tiles, 40 tiles cover the area; a 10% allowance gives 44 tiles.
Good to know
Ignores grout width and specific cutting patterns. Pack-size rounding, edge pieces and supplier-specific waste allowances need separate review.
Area coverage is not a cutting layout
Forty 50 by 50 cm tiles have a combined face area of 10 m². A room of that area can still need extra tiles because the boundary cuts and pattern may not let every offcut be reused.
That is why the allowance is separate from geometric coverage. A diagonal pattern, irregular room or fragile material can behave differently from a simple rectangular layout. The default allowance is an editable estimate, not a universal requirement.
Convert tile dimensions before combining areas
The surface area is in square metres but tile sides are entered in centimetres. The tool multiplies the tile sides and divides by 10,000 to convert square centimetres to square metres.
Grout width, edge trim and pack sizes are not modeled. Check whether the supplier sells by tile, pack or nominal coverage, then round the purchase accordingly. The tool rounds an estimated count to whole tiles only.
A few questions, answered
Does this include grout spacing?
No. It uses the tile face dimensions and a separate allowance.
Why is the answer rounded up?
A fractional tile cannot normally be purchased as a full usable tile; the estimated purchase count uses whole tiles.