How to Calculate Tile Cost — Step by Step

The short answer

To work out what tiling a room costs, measure the room, work out the room area, add the waste, and price the tile, the grout and the labour. For a 12 by 10 foot room that gives 120 square feet of room and 132 square feet billable, which costs $1,551.00 in total.

The three numbers that matter

The first number is the room area, which is the length times the width, so the room area is 120 square feet. The second number is the billable area, which is the room area plus the waste. Ten percent waste is standard for a square room, so 120 times 1.10 is 132 square feet billable.

The third number is the total, which is the billable area times the three rates added together. The tile is $5.00 a square foot, the grout and thinset are $0.75, and the labour is $6.00, so the three rates add to $11.75 a billable square foot. The tile costs 132 times $5.00, which is $660.00, the grout and thinset cost 132 times $0.75, which is $99.00, and the labour costs 132 times $6.00, which is $792.00. The total is $1,551.00, or $12.93 per room square foot.

The method

The method is two multiplications and an addition. One: multiply the length by the width to get the room area. Two: multiply the room area by one plus the waste over 100 to get the billable area. Three: multiply the billable area by each of the three rates, tile, grout and thinset, and labour, and add the three together. The waste is the part people skip, and it is the part that stops the job before the last row, so it is worth getting right. Check it with the cost per room square foot.

Step by step

Step 1: find the room area. Measure the room wall to wall at the longest points, in feet. For a 12 by 10 foot room that is 12 times 10, which is 120 square feet.

Step 2: find the billable area. Multiply the room area by one plus the waste over 100. For this room that is 120 times 1.10, which is 132 square feet. The waste is 12 square feet of tile that is cut at the edges and around fixtures, and the offcuts cannot be reused, so skipping this step underbuys tile.

Step 3: price the tile. Multiply the billable area by the tile price. For this room that is 132 times $5.00, which is $660.00. This is the second biggest of the three costs, and it moves the most when you change the tile.

Step 4: price the grout, the thinset and the labour. The grout and thinset are 132 times $0.75, which is $99.00, and the labour is 132 times $6.00, which is $792.00. The labour is the biggest of the three costs, more than half the total, which is why doing it yourself saves so much.

Step 5: add the three together and check. The total is $660.00 plus $99.00 plus $792.00, which is $1,551.00. The check is the cost per room square foot: $1,551.00 divided by 120 is $12.93, the number to compare between rooms and between tiles.

The worked example

A homeowner is tiling a 12 by 10 foot bathroom, and the shop charges $5.00 a square foot for tile, $0.75 for grout and thinset, and $6.00 for labour. The room area is 12 times 10, which is 120 square feet. The billable area is 120 times 1.10, which is 132. The tile costs 132 times $5.00, which is $660.00. The grout and thinset cost 132 times $0.75, which is $99.00. The labour costs 132 times $6.00, which is $792.00. The total is $1,551.00, or $12.93 per room square foot.

A bigger room, and other round numbers

Some rooms are worth knowing by heart. A 15 by 12 foot room is 180 square feet, 198 billable with 10 percent waste, which costs $2,326.50. Tile at $10 a square foot instead of $5 costs $1,320.00 for the tile alone, and the total rises to $2,211.00. Waste at 15 percent instead of 10 gives 138 billable square feet, and the total is $1,621.50. Doing the labour yourself, at $0 instead of $6.00, brings the total down to $759.00.

Working backwards from a budget

To find how big a room a budget covers, add the three rates together, divide the budget by that rate, and divide by one plus the waste over 100. A $2,000 budget divided by $11.75 a billable square foot buys 170.21 billable square feet. Divide that by 1.10 for the waste, and it covers a 154.74 square foot room, bigger than the 120 of this room, so $2,000 covers the room with room to spare.

Common mistakes

The most common mistake is pricing the room area, not the billable area. A 12 by 10 foot room is 120 square feet of room but 132 billable, so pricing the room buys 12 square feet short, and the job stops before the last row. The second mistake is forgetting the grout and thinset, $99.00 here. The third is forgetting the labour, $792.00, more than half the total. The fourth is using 10 percent waste for a diagonal pattern, which needs 15 percent. The fifth is measuring the room at the skirting board instead of wall to wall, which loses a few inches on every side.

The verdict

A 12 by 10 foot room costs $1,551.00 to tile: 120 square feet of room, 132 square feet billable, $660.00 of tile, $99.00 of grout and thinset, and $792.00 of labour. Measure the room, add the waste, and price the three parts. Check the numbers yourself on the tile cost calculator, work out the carpet for the same room with the carpet cost calculator, or check the floor over 25 years with the vinyl plank vs laminate flooring calculator.