Tile Calculator
How much tile do you need? Measure any number of rooms, add a waste factor, and get the square footage, quantity and cost to order.
A worked example
A 12 × 15 ft room is 180 square feet. Adding the 10% waste factor this calculator defaults to brings that up to 198 square feet to buy — 14 boxes, at 15 sq ft each. At the mid-range price of $12.00 per square foot that is about $2,376.00.
| Grade | Price per sq ft | 180 sq ft room, installed |
|---|---|---|
| Budget | $7.00 | $1,386.00 |
| Mid-range | $12.00 | $2,376.00 |
| Premium | $20.00 | $3,960.00 |
Price ranges are broad US ballpark figures for material plus typical installation, gathered as placeholders and not yet verified against sourced pricing. Use them to sanity-check a quote, not to replace one. A box of 12×12 in tile typically holds 15 pieces covering 15 sq ft. Larger formats vary widely.
To compare quotes on the same basis, see how to calculate price per square foot.
Working out how much tile to buy
Start with the area you are tiling, add the waste allowance, then divide by the coverage per box and round up. A 180 square foot floor at 10% waste needs 198 square feet of tile; at 15 square feet a box that is 13.2 boxes, so you order 14. Rounding down is how a job stops on its last afternoon.
Buy the whole order at once. Tile is fired in batches and the dye lot varies between them, sometimes visibly. A replacement box bought a year later will rarely match well enough to sit in the middle of a floor.
Waste factors that hold up in practice
Ten percent is right for a straight lay in a simple rectangular room. Fifteen is the figure for a diagonal or herringbone pattern, where every tile meeting a wall is a cut and the offcut is a triangle you cannot reuse. Add another five points for a room with many corners, an alcove, or a curved edge — anything that turns a full tile into two unusable halves.
Large-format tiles waste more than small ones for the same reason: the piece you cut off is bigger.
Floors, walls and backsplashes
For a floor, subtract anything permanently fixed to it that you will not tile under — a run of base cabinets, an island plinth, a bath panel — but tile under toilets and free-standing appliances, and let the cuts come out of the allowance.
For a wall, multiply width by height for each wall and subtract the openings. A backsplash is a long strip: run length × height, so 12 feet of counter with an 18 inch backsplash is 18 square feet. Small areas need a proportionally larger allowance — add 15%, and at least one extra square foot regardless, because a single cracked tile on a 15 square foot job is a real risk.
Frequently asked questions
How do I calculate how much tile I need?
Work out the area to be tiled in square feet, add a waste allowance, then divide by the square footage each box covers and round up. A 180 square foot floor with 10% waste needs 198 square feet of tile; at 15 square feet a box that is 13.2 boxes, so you buy 14. Never round down — a box is the smallest unit you can buy, and running short mid-job is the expensive outcome.
How much extra tile should I buy for waste?
Ten percent for a straight lay in a simple rectangular room, and 15% for a diagonal or herringbone pattern, where every edge piece is a cut. Add another 5% for a room with many corners, alcoves or a curved edge. Buy the extra in the same order rather than later: dye lots vary between production runs, and a replacement box bought a year on rarely matches.
Do I subtract cabinets, islands and fixtures from a tile calculation?
Subtract anything permanently fixed to the floor that you will not tile under — a run of base cabinets, an island with a plinth, a bath panel. Do not subtract a toilet or a free-standing appliance: you tile under those, and the cut pieces come out of the waste allowance anyway. If you might refit the kitchen later, tiling through under the cabinets is worth the extra material.
How do I calculate tile for a wall or a backsplash?
Measure each wall's width by its height and add them, then subtract the openings. A backsplash is usually a long strip: run length × height, so 12 ft of counter with an 18 in backsplash is 12 × 1.5 = 18 square feet. Backsplashes are small enough that the waste allowance matters more in percentage terms — add 15%, and at least one extra square foot regardless.