Running out of tile halfway through a job is frustrating, and the next batch may not match exactly. Measuring carefully and adding the right amount of extra avoids both problems.

Step 1: Measure the area

Measure length and width in feet and multiply. A 10 × 8 ft bathroom floor is 80 sq ft. For L-shaped or irregular rooms, split the space into rectangles, calculate each, and add them up. Subtract areas you won’t tile, such as under a vanity or tub.

Step 2: Work out the area of one tile

Tile sizes are given in inches. Multiply length by width and divide by 144 to convert to square feet:

12 × 24 in tile = 288 ÷ 144 = 2 sq ft
12 × 12 in tile = 144 ÷ 144 = 1 sq ft
3 × 6 in subway tile = 18 ÷ 144 = 0.125 sq ft

Step 3: Divide and add waste

In the example, 80 sq ft ÷ 2 sq ft = 40 tiles. Now add extra for cuts, breakage and future repairs:

• About 10% for a straight layout: 40 × 1.10 = 44 tiles.
• About 15% for diagonal or herringbone patterns.
• More for rooms with many corners or for large-format tiles, where each cut wastes more.

Our Tile Calculator does this math and converts the result into boxes.

Step 4: Convert to boxes

Tile is sold by the box, and the label shows either the number of tiles or the square footage per box. Divide your total by that number and round up. Check that every box has the same lot or batch number, since color can vary slightly between production runs.

Don’t forget the other materials

• Thinset or adhesive: the bag lists coverage, which depends on the trowel notch size.
• Grout: the amount depends on tile size, joint width and depth; check the manufacturer’s chart.
• Underlayment or backer board for floors and wet areas.
• Spacers, sealer and edge trim where needed.

Key takeaways

• Tile area in sq ft = length × width (inches) ÷ 144.
• Add 10% for straight layouts and 15% for patterns.
• Buy all boxes from the same lot and keep a few spares.