Tile Calculator

1. Enter room dimensions. Measure the length and width of the room in feet. For L-shaped rooms, break the space into two rectangles, calculate each separately, and add the tile counts together. For bathrooms with a tub, subtract the tub footprint from the floor area.
2. Select or enter tile size. Use the preset buttons for the most common sizes (4x4, 6x6, 12x12, 18x18, 24x24, 3x6), or type custom dimensions in inches. The calculator automatically accounts for the grout gap when computing how many tiles fit in the space.
3. Set the grout gap. The default is 1/8 inch (0.125 in), which is standard for most floor and wall tiles. Rectified tiles (precision-cut) can use a 1/16 inch gap. Rustic or handmade tiles often need 3/16 to 1/4 inch gaps. The grout gap meaningfully affects tile count for large areas.
4. Adjust the waste factor. Use 10% for simple rectangular rooms with straight cuts. Use 15% for diagonal patterns or rooms with many corners. Use 20% for herringbone, chevron, or other complex patterns. Keep a few extra tiles for future repairs.

Example: a 12 x 10 ft bathroom floor using 12x12 tiles with a 1/8 inch grout gap needs 121 tiles net. With 10% waste, order 134 tiles. That is 134 square feet of tile to buy, since each 12x12 tile is 1 ft².

The tile calculator uses grout-adjusted tile dimensions so the count is accurate regardless of joint width. A 12-inch tile with a 1/8-inch grout gap effectively occupies 12.125 x 12.125 inches of floor space.

Grout is sold in 10 lb bags. For 1/8-inch joints, plan on 1 lb of grout per 2 square feet of 12x12 tile. For narrower joints or larger tiles, you need less grout. Sanded grout is used for joints wider than 1/8 inch. Unsanded grout is for joints 1/8 inch or less, including most wall tile applications where wider grout lines would slump before curing.