◻️ Tile Calculator

What This Calculator Does

This calculator turns a tiling job into a purchase count. Enter the area to cover, the tile's dimensions in inches, and a waste percentage, and it tells you how many tiles to buy — the base count and the count with waste included. Floors, walls, showers, and backsplashes all use the same math with different inputs.

Tile is sold in boxes, discontinued without warning, and varies subtly between dye lots — which together make buying the right amount once genuinely important. The calculation is simple; the judgment is in the waste factor, and this tool builds both in.

The Tile Math, Properly Done

The core is area division. One 12 × 12-inch tile covers exactly one square foot, so 120 sq ft needs 120 tiles before waste. Other sizes convert through square inches: a 12 × 24 tile covers 288 sq in (2 sq ft), a 3 × 6 subway tile 18 sq in (0.125 sq ft — eight per square foot). The general formula the calculator applies: tiles = (area in sq ft × 144) ÷ (tile width × tile height in inches), rounded up, then multiplied by (1 + waste).

Waste is not pessimism — it is physics and prudence. Every row that meets a wall ends in a cut tile, and the offcut frequently cannot be used elsewhere; tiles break in transit and installation; layouts rarely divide evenly into rooms. The standard 10% covers straight-lay in ordinary rooms. Diagonal and herringbone patterns generate more unusable offcuts — plan 15%. Small rooms and busy perimeters (toilets, alcoves, doorways) raise the cut ratio; very large-format tile amplifies each breakage. When in doubt, the higher figure costs one box now and saves a discontinued-tile hunt later.

Floors, Walls, and Backsplashes

Floors are the straightforward case: room area (length × width, alcoves added) through the formula. Walls add subtraction: length × height minus windows, doors, and the tub or vanity footprint the tile will not cover. A standard backsplash is the counter run times roughly 18 inches of height — a 10-foot counter is about 15 sq ft, which in 3 × 6 subway tile is 120 tiles before waste, a number that surprises people used to thinking in big-tile counts.

Showers combine both: each wall computed separately (minus the valve wall's openings if you insist on precision), floor added if tiled, and a niche's interior surfaces are small but real. Because each surface may use a different tile — floor mosaic, wall field tile, accent band — run each through the calculator separately with its own size and waste. Trim pieces (bullnose, edge profiles) are counted by linear foot rather than area and bought alongside; they are the piece estimates most often forget. The calculator handles every area-based count; a sketch with measurements handles remembering all the surfaces.

Buying Tile Like You Have Done It Before

Tile sells by the box, and the box dictates the final number: if coverage per box is 14.7 sq ft and you need 132 sq ft with waste, you buy ten boxes (147 sq ft), not nine — always rounding boxes up. Check the dye-lot number on every box at pickup; lots vary subtly in shade, and a mixed-lot floor can show it in raking light. The professional habit worth copying: buy the full amount plus the waste at once from a single lot, and store a few leftover tiles permanently — a cracked tile three years in is a five-minute repair with a matching spare and a renovation without one.

The waste margin also quietly funds pattern freedom. Centered layouts (start the pattern mid-room so cuts balance at the walls) look dramatically better than starting from one wall, and they consume slightly more tile — margin money well spent. Before purchase, dry-lay a row or compute the cut sizes at each wall: if a layout ends in slivers under half a tile wide, shifting the start line half a tile produces fuller cuts and a cleaner look at identical cost. The calculator supplies the honest quantity; these habits turn the quantity into a floor that looks deliberate.

Quick Tips

• Tiles = (sq ft × 144) ÷ (tile W × H in inches), plus waste.
• 10% waste for straight lay; 15% for diagonal, herringbone, and small rooms.
• Buy whole boxes from one dye lot and keep spares for repairs.
• Center the layout so cuts balance at the walls — slivers look accidental.

Frequently Asked Questions

How many tiles do I need?

Divide the area by one tile's area, then add waste. For 120 sq ft of 12 x 12-inch tile (1 sq ft each) with 10% waste: 120 tiles + 12 = 132. The calculator handles any tile size in inches.

How much extra tile should I buy for waste?

10% is the standard for straight layouts; diagonal patterns, herringbone, small or oddly shaped rooms, and large-format tile justify 15%. Cuts, breakage, and future repairs consume the margin — and matching a discontinued tile later is far harder than storing a spare box.

How do I calculate tiles for a wall or backsplash?

The same way: wall length x height gives the area, minus openings like windows. Backsplashes are typically the counter length times about 18 inches of height. Run the area through with your tile size and waste.

Do I count grout lines in the math?

For estimating, no — grout joints slightly reduce tile count, so ignoring them adds a small hidden margin in your favor. Layout planning uses them, but purchase math safely treats tiles as covering their full size.

Exact, Practical, and Free

This calculator runs entirely in your browser, counting tiles the moment you type. It needs no account or download and works on any device. Like every tool here, it is free to use as often as you like.

Related Tools

For more renovation math, the square footage calculator measures the area, the paint calculator covers the walls above, and the percentage calculator applies the waste margin.