How Many Boxes of Tile Do I Need?

Updated October 31, 2026

Tile is a count of pieces, then a count of boxes. Square footage tells you the floor. It does not tell you how many tiles fit once a grout joint takes space, and the store will not split a carton to match a fraction of a box. Plank flooring sold by the square foot on the carton is a different purchase.

Measure the area you will tile

Measure the length and width of the finished floor, out to where the tile stops. Feet are fine. An alcove is a second rectangle. Run the numbers once per rectangle and add the boxes. Do not average the two widths into one room. Averaging undercounts the larger part.

Add the grout gap, then count each side

Convert the room and the tile to inches. The pitch of one tile is the face size plus the grout gap. Count how many pitches fit along the length, and how many fit along the width, rounding each side up. Multiply those two counts. That is the grid before waste.

A 1/8 inch joint is 0.125 inches. Use 0 when you are laying rectified tile tight, with no joint. The gap is the joint you will leave. It is not the spacer size plus a guess.

A 10 by 12 foot floor with 12 by 12 inch tile

Grout gap 1/8 inch. Twenty tiles in a box is only the count for this example. Use the number printed on the carton you will carry out.

• Room in inches: 10 × 12 = 120 along one side, and 12 × 12 = 144 along the other.
• Pitch: 12 + 0.125 = 12.125 inches.
• Along 120 inches: 120 ÷ 12.125 is just under 10, so the count rounds up to 10 tiles. Ten pitches are 121.25 inches, which covers 120.
• Along 144 inches: 144 ÷ 12.125 is just under 12, so the count rounds up to 12 tiles.
• Tiles in the grid: 10 × 12 = 120.

The same room with the grout gap set to 0 is also 120 tiles, because 120 and 144 divide evenly by 12. The joint changes the count when a leftover strip is smaller than the gap you typed. Enter the joint you will use. Do not leave the field at 1/8 inch if you are grouting at 3/16.

Add waste, then buy whole boxes

120 tiles is the grid. It does not include a tile you break or a cut around a closet flange. The waste choices are 0, 5, 10, 15, and 20 percent.

• 5% — a straight layout, few cuts, and a simple rectangle.
• 10% — the default. 120 × 1.10 = 132 tiles.
• 15% — a diagonal layout, or several cuts around a toilet and a vanity.
• 20% — a pattern that throws away offcuts, or a small room where one broken tile is a large share of the job.

132 ÷ 20 = 6.6 boxes. The order rounds up to 7 boxes. You cannot buy six-tenths of a carton, and the tiles left in the seventh box are what you keep when a tile chips later. With the gap at 0, the count before waste is still 120, and 10 percent still lands on 7 boxes.

This is not the plank flooring calculator

Plank and vinyl cartons are often labeled in square feet of coverage. The flooring notes turn the room into square feet, add a waste percent, and divide by that coverage: Flooring Square Footage With Waste Allowance. Tile cartons are often labeled by the piece. Dividing 120 square feet by a guessed coverage can miss the partial row that the side count catches. Use the tile count for tile.

What the box count leaves out

Thinset, grout mix, and trim are not inside the box count. This page does not estimate pounds of grout. Buy those from the coverage on their own labels. Color can shift by dye lot. Take the boxes from one lot, and open more than one box before the first row is set. If you type a price per box, the cost line is that price times the boxes. In this example that is 7. It is not tax, thinset, or delivery.