Tile Calculator
Estimate how many tiles to buy for a floor, wall or splashback. Enter the area and tile size, allow for grout joints and waste, and get a tile and box count.
10% for straight layouts; 15% or more for diagonal or herringbone.
Tiles = area ÷ (tile + grout joint footprint), rounded up, then increased by the waste allowance for cuts, breakage and pattern matching. Boxes are rounded up to whole boxes, so you usually end up with a few spare tiles. Real installations often need extra for borders, niches and future repairs — buy from the same batch so colours match.
120 sq ft
Room area
144 sq in
Area of one tile
118
Tiles (no waste)
130
Tiles incl. 10% waste
Add tiles per box
Boxes
Add tiles per box
Estimated cost
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How to use tile calculator
- 1Choose US (feet and inches) or metric units.
- 2Enter the length and width of the area to tile.
- 3Enter the tile size and the grout joint width.
- 4Set a waste allowance and, optionally, how many tiles come in a box and the price per box.
- 5Read the tiles needed, boxes to buy, spare tiles left over and estimated cost.
About this tool
The calculator divides the area by the footprint of one tile plus its grout joint, rounds up, then adds your waste allowance. Waste covers tiles cut at the edges, breakages and pattern matching: around 10% is usual for a straight layout in a simple room, and 15% or more for diagonal, herringbone or large-format tiles.
Example: a 12 × 10 ft floor is 120 sq ft. With 12 × 12 in tiles and no grout gap, that's 120 tiles — 132 with 10% waste, or 14 boxes of 10. Because boxes are whole, you'd buy 140 tiles and have 8 spare; at $25 a box the tiles cost about $350.
This is an estimate for rectangular areas. For L-shaped rooms, work out each rectangle separately (or use the Square Footage Calculator) and add them. Real installations may need extra tiles for borders, niches and future repairs, and it's wise to buy all tiles from the same batch so the colour matches.
Frequently asked questions
About 10% for a standard straight layout, 15% for diagonal or herringbone patterns, and more for complicated rooms or large tiles that produce more offcuts. Keeping a few spare tiles also helps with future repairs.
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