Tile calculator: how many tiles do I need?

How many tiles do I need? The math in words

1. Work out the area: length times width, both in feet. For an L-shaped room, add rectangles; the square footage calculator walks through odd shapes.
2. Add the extra for cuts: 10% for a straight grid, 15% for a diagonal or herringbone lay, which needs more cuts at the edges and corners.^[1]
3. Work out one tile's area: its width times its length in inches, divided by 144, the square inches in a square foot.^[2]
4. Divide the area with the extra by one tile's area and round up. That is the tile count.
5. Divide by the tiles in a box, from the box label, and round up to whole boxes.

Example: a 10 by 12 foot kitchen in 12 by 24 inch tile, laid straight. Area: 120 square feet; plus 10% makes 132. One tile: 12 × 24 ÷ 144 = 2 square feet. Tiles: 132 ÷ 2 = 66. With 8 tiles to a box, that is 66 ÷ 8 = 8.25, so 9 boxes. Laid on the diagonal, the 15% extra makes 138 square feet and 69 tiles, still 9 boxes.

Straight, diagonal or herringbone: how much extra tile

Floor & Decor tells buyers to order at least 10% over for a standard grid and 15% for diagonal, herringbone or other patterns, because the pattern needs more cuts at the edges and corners.^[1] The calculator starts at 10%; type 15 in Extra for cuts and waste for a pattern. The count uses the tile's own size and leaves out the grout joint, so the joint adds a little spare on top.

Buy whole boxes and keep the leftover tiles: a cracked tile years later is easy to replace from the same batch, and hard to match from a new one.

Tile for a shower wall or a backsplash

A wall is a rectangle too: its width times the height the tile goes up. In the calculator, type each wall's width as the length and the tiled height as the width, and press Add a rectangle for the next wall. Set a window or a niche to Cut out.

Example: a tub shower tiled 6 feet up, with a 5 foot back wall and two 2 foot 6 inch end walls. Back: 5 × 6 = 30 square feet. Ends: 2.5 × 6 = 15 each. Total 60, plus 10% is 66 square feet. In 3 by 6 inch subway tile, one tile is 3 × 6 ÷ 144 = 0.125 square feet, so 66 ÷ 0.125 = 528 tiles.

Floors and walls from the same walk

A tile quote needs the floor of every room and the walls of every bathroom, which usually means a tape, a notepad and a sketch. PlaceAnew gets it in one walk. Hold an iPhone or iPad with LiDAR (iPhone 12 Pro or a newer Pro model, or an iPad Pro from 2020 or later), walk through, and the floor plan comes out with every room named and measured, its square footage and the total. The Measure tool reads any distance on the plan, and the PDF report gives the average ceiling height, so the wall math is ready too. The scan also reads the floor that is there now, marked "estimate" when it is not sure, so the quote starts with what comes out.

The sizes hold up: in one walk of our own office, the office came out at 195 square feet against 197 on the hand-measured plan.^[3] Scanning, floor plans, 3D, editing, the kitchen designer with prices and exports are free. Estimate flooring from an iPhone scan shows the whole order from one scan.

Questions people ask