🔲Tile Calculator

Use this tile calculator to find out exactly how many tiles you need for any floor, wall, or backsplash project. Enter the room dimensions, the tile size, a waste percentage, and optionally the grout line width and the number of tiles per box. The calculator returns the total tile count, box count, and estimated material cost, so you can buy the right amount on the first trip to the tile store.

Floor Tile Calculator with Square Footage

The foundation of any tile estimate is the room's square footage. Multiply the room length by the room width to get the total floor area. For an irregular room, break it into rectangles, calculate each section separately, and add the results. Subtract any large fixed obstacles that will not be tiled, such as a kitchen island with a fixed base, but do not subtract for toilets, vanities, or cabinets that might be removed in the future. Tiling underneath removable fixtures makes repairs and replacements easier later.

Once you have the room's square footage, divide by the area of a single tile to get the base tile count. A 12-inch by 12-inch tile covers exactly 1 square foot. An 18-inch by 18-inch tile covers 2.25 square feet. A 24-inch by 24-inch tile covers 4 square feet. This calculator handles any tile size in inches, centimeters, or millimeters, converting to square feet automatically for the comparison.

Tile size affects the visual appearance of a room. Larger format tiles such as 18 by 18 or 24 by 24 reduce the number of grout lines, which can make a small room feel more open and expansive. However, large tiles require an exceptionally flat and level subfloor. Any deviation greater than about 1/8 inch over 10 feet creates hollow spots beneath the tile, which leads to cracking over time. Medium tiles in the 12 by 12 or 12 by 24 range are the most widely used because they balance visual appeal with reasonable subfloor tolerance. Small mosaic tiles are the most forgiving of minor subfloor variation.

How to Calculate the Number of Tiles for a Room

Follow these steps to calculate the number of tiles for a room accurately:

• Step 1: Measure the room length and width. For non-rectangular spaces, divide into sections and measure each.
• Step 2: Multiply length by width to get total square footage.
• Step 3: Calculate the area of one tile in square feet (tile length in inches x tile width in inches, divided by 144).
• Step 4: Divide the room area by the tile area and round up to the nearest whole number.
• Step 5: Multiply by your waste factor (1.10 for 10 percent waste, 1.15 for 15 percent, 1.20 for 20 percent).
• Step 6: Divide by the number of tiles per box and round up to get the box count.

Always buy tiles from the same production run, called a dye lot. Tile color and texture can vary slightly between manufacturing batches. If you run short mid-project and the new supply comes from a different dye lot, the difference may be visible after installation. Buying all your tiles in one purchase from the same dye lot, plus at least one extra box, avoids this problem and gives you spare tiles for future repairs.

Tile Calculator with Waste and Grout Lines

Waste percentage accounts for tiles that must be cut to fit the edges of a room, corners, outlets, and other obstacles, as well as tiles that crack or chip during cutting. The right waste percentage depends on the layout pattern and room complexity:

• Straight grid layout in a simple rectangular room: 10 percent
• Diagonal (45-degree) layout: 15 percent, because diagonal cuts waste more tile material at the room's perimeter
• Rooms with many obstacles such as bathroom fixtures, doorways, or irregular walls: 15 to 20 percent
• Natural stone or handmade tiles with more variation and breakage: up to 20 percent

Grout line width, also called the joint width, affects the total tile count because each tile's effective footprint includes the grout line on two of its sides. A tile with a 3/16-inch grout joint occupies slightly more floor area than the tile's nominal dimensions suggest. For most standard ceramic and porcelain tiles, a 3/16-inch joint is typical. Rectified tiles, which are precision-cut to exact dimensions, can use narrower joints as small as 1/16 inch. Larger natural stone tiles with dimensional variation typically require 1/4 to 3/8-inch joints to accommodate the differences. The grout line width field in this calculator lets you account for this effect exactly.

Subfloor condition is the most overlooked factor in tile installation planning. Ceramic and porcelain are rigid materials that crack under any flexing. Wood subfloors require cement backer board, such as HardieBacker or Durock, installed directly over the subfloor before tiling. Concrete subfloors can generally be tiled directly if they are flat, free of cracks, and structurally sound. An out-of-level subfloor must be corrected with a self-leveling underlayment before installation begins. Skipping this step is the most common cause of tile cracking and grout failure within the first few years after installation.