Tile and Flooring Calculator

Tip: check that every box has the same lot or batch number before you start. Tile and plank colors vary between production runs.

Worked example

A 12 ft by 10 ft kitchen floor is 120 square feet. With 10% extra for cuts and breakage you need 132 square feet of material.

At 15 square feet per box, 132 / 15 = 8.8, so you buy 9 boxes, which covers 135 square feet. Keep any unopened leftovers for future repairs, or return them if the store allows.

How to calculate tile and flooring

Multiply the room length by width to get square feet. Add a waste allowance for cuts, breakage and future repairs, then divide by the square feet each box covers. The coverage is printed on the box or listed on the product page. Always round up to whole boxes.

For L-shaped rooms, split the floor into rectangles, calculate each one and add them together. Include closets and the area under appliances that will be removed, such as a dishwasher you plan to tile under. Do not subtract small items like vanity bases unless you are sure they will never move.

How much waste to allow

• Straight lay in a simple rectangular room: 10%.
• Diagonal layouts: 15%, because every edge piece is cut on an angle.
• Herringbone and chevron patterns: 15% to 20%.
• Large format tile, natural stone or rooms with many corners: 15%.
• Laminate and vinyl plank in a simple room: 5% to 10%, since offcuts from one row usually start the next.

Smaller rooms waste a bigger share of material than large ones, because a higher fraction of pieces are cut at the walls.

Counting tiles instead of boxes

If tile is sold by the piece, divide the square footage by the area of one tile. A 12 x 24 inch tile is 2 square feet, so 132 square feet takes 66 tiles. A 12 x 12 tile is 1 square foot. For tiles in inches, multiply the two sides and divide by 144 to get square feet.

Grout joints add a little coverage, since each tile effectively covers its size plus half the joint on each side, but not enough to change the order on most floors. Ignore them and keep the waste allowance.

Other materials for a tile job

• Thinset mortar: a 50 lb bag covers roughly 40 to 95 square feet, depending on the trowel notch. Large tiles need bigger notches and more mortar.
• Grout: depends on tile size and joint width. The bag label has a coverage chart.
• Underlayment or backer board for floors that need it, sold in 3 x 5 ft sheets of 15 square feet.
• Transition strips at doorways and spacers for consistent joints.

For floating floors like laminate and vinyl plank, add underlayment if the planks do not have it attached, and transition and baseboard trim to cover the expansion gap at the walls.

Why keep extra tile

Keep at least one spare box after the job. Tile and plank batches vary in color, and a matching piece can be hard to find years later when one cracks or water damages a section. Store the spares somewhere dry with the product name and lot number written on the box.

Measuring tips for floors

Measure each room at the widest points, wall to wall, and include doorways where the new floor will run under the door. For flooring that continues through several rooms, measure each one separately and add them, since every room has its own edge cuts. If walls are out of square, use the larger measurement on each side. Check that all your measurements are in feet before multiplying, and convert inches by dividing by 12.

More calculators

Results are estimates, not a contractor quote. Check quantities with your supplier before you order, and follow local building codes.