How this calculator works
It finds the area you’re covering and the area of a single tile, divides one by the other, then adds a waste allowance for cuts and breakage and rounds up to whole tiles and boxes.
Area 100 sq ft, each tile 1 sq ft → 100 tiles. Add 10% → 110 tiles (11 boxes of 10).
Order tile by box coverage and layout
Cut edges, the occasional break, and future repairs all eat into your count. 10% is standard; use 15–20% for diagonal or herringbone layouts. Measure doorways, floor vents, and built-in cabinets separately before subtracting them from the field area; avoid subtracting small openings that will still require cut tiles. Enter the square-foot coverage printed on the box so the calculator can round your purchase up to whole boxes; this is more reliable than inferring box count from nominal tile dimensions when package coverage differs. If the package coverage differs from the nominal tile size, use the package coverage to make the purchase decision. Compare the calculator's tile count with the coverage printed on the box. Buy each product as a separate order because floor, wall, trim, and mosaic boxes can have different coverage and dye lots. Buy all visible-field tile from the same dye lot when possible, and keep a few uncut pieces for future repairs. Dry-lay a few rows and plan the cuts at opposite walls before opening every box. After choosing tile, estimate setting material with the thinset calculator and joints with the grout calculator.
Frequently asked questions
How many 12×12 tiles for 100 sq ft?
110 tiles — 100 for the area plus 10% waste.
How much tile overage do I need?
Use 10% for a rectangular field with a straight layout, 15% when the room has many cuts or the layout is offset, and 20% for diagonal or herringbone patterns. A 120 sq ft bathroom at 15% needs 138 sq ft of tile before box rounding; then divide by the box coverage and round up.
Does tile overage include box rounding?
No. Apply the waste allowance to the measured area first, then round the result up to whole boxes. If a 100 sq ft floor needs 110 sq ft after a 10% allowance and each box covers 12.5 sq ft, round 8.8 boxes up to 9. The final purchase covers 112.5 sq ft; the extra 2.5 sq ft comes from package rounding, not a larger waste percentage.
How much extra tile should I keep for future repairs?
Keep at least one unopened box when the budget and storage allow. It gives you matching replacements if a tile cracks later, because the same product can change shade or be discontinued.
How many tiles do I need for a bathroom or shower?
Measure each wall or floor section separately, add the areas together, then add 10–15% for cuts, niches, corners, and breakage.
How do I calculate how many tiles I need?
Multiply the length and width of the area for square feet, divide by the area covered by one tile, then add a waste allowance and round up.