Running out of tiles mid-floor — or worse, finishing with a mismatched dye lot — is the classic tiling disaster. This tile calculator works out how many tiles and boxes you need for a floor or wall, including the waste allowance the pros always add.
How many tiles do you need?
Divide the surface area by the area of one tile, add waste, and round up. Worked example: a 10 × 8 ft bathroom floor (80 sq ft) in 12 × 12 in tiles (1 sq ft each) needs 80 tiles; with 10% waste, 88 tiles — at 10 tiles per box, that's 9 boxes. Enter room and tile sizes in any units; the calculator keeps everything consistent and rounds up to whole tiles and boxes.
How much waste to allow
Allow about 10% for straight layouts and 15–20% for diagonal, herringbone or patterned installs — every cut edge is a potential offcut you can't reuse. Small rooms with many fixtures (toilets, vanities) also chew through cuts. Waste isn't pessimism; it's what keeps you from a second store trip and a mismatched batch.
Buy by the box, from one lot
Tiles are sold by the box, and color varies subtly between production runs. Buying all boxes from a single dye lot (check the batch number on the box) ensures a uniform floor — and keeping a few spares means future repairs match perfectly.
Planning the whole job
Measure irregular rooms by splitting them into rectangles with the square footage calculator. Tiling a wall? Same math — area ÷ tile size + waste. And if the subfloor needs a fresh screed first, estimate it with the concrete calculator.