Tile Calculator

Take the area to tile in square feet, add waste for the pattern (about 10 percent for a straight lay), and divide by the area one tile plus its grout joint covers. A 100 square foot floor of 12 × 12 tile is about 110 tiles with 10 percent waste. Round up to whole boxes and add one spare box for repairs. This calculator does all of it, including the thinset and grout.

Measure the length times the width for the area, or add up the rectangles for an irregular room, and subtract large openings. Multiply the area by 1 plus the waste (1.10 for a straight lay), then divide by the footprint of one tile plus its joint. For a 12 × 24 tile that footprint is about 2 square feet, so a 200 square foot floor at 15 percent waste is 230 divided by 2, or 115 tiles.

By the tile face, 100, because a 12 by 12 inch tile is exactly one square foot. A nominal 12 is really about 11 and 7 eighths inches and already assumes a grout joint, so with the joint counted it still comes out right around 100 per 100 square feet. Add 10 percent for a straight-lay waste and you would buy about 110 tiles, which is 8 boxes of 15.

A 12 by 24 inch tile covers 2 square feet, so about 50 tiles for 100 square feet by the face. A 12 × 24 is large-format, so a straight lay adds 15 percent waste (10 percent base plus 5 for large-format), which comes to about 58 tiles, or 8 boxes of 8. A 24 × 24 tile covers 4 square feet, so it is about 25 per 100 square feet, or 29 with waste.

Yes, but it lowers the count, it does not raise it. A tile plus its grout joint covers a little more area than the bare tile, so you need slightly fewer. The common mistake is to add a joint on top of the nominal size and buy too few, because a nominal 12 inch tile is really about 11 and 7 eighths inches and already assumes one joint. This calculator folds the joint in the right direction.

Add about 10 percent for a straight lay, 15 percent for a diagonal, and 18 percent for herringbone, plus another 5 percent for large-format tile. A cut-up room with lots of corners can need a few points more. Waste covers the cut pieces and breakage during the install. On top of the waste, buy one extra box of attic stock for future repairs.

Attic stock is a spare box of tile you keep after the job for future repairs. Keep at least one full box. It matters because tile is made in batches, and the color and print of a dye lot vary between runs, so a tile you buy a year later to replace a cracked one will not match. Attic stock is separate from the waste allowance, which is consumed during the install.

It depends on the trowel, which is set by the tile size. A 50 pound bag covers about 85 square feet under small tile with a 1/4 inch notch, about 60 under a 12 inch tile, and only about 30 under large-format tile, which needs a 1/2 inch notch and back-buttering. A 100 square foot floor of 12 × 12 takes about 2 bags; the same floor in 12 × 24 takes about 4.

Because coverage is set by the trowel notch, and the notch is set by the tile size. A small tile uses a shallow 1/4 inch notch that spreads thin and covers a lot, while a large-format tile needs a deep 1/2 inch notch plus a back-butter coat, which uses more than twice the mortar for the same floor. A single coverage number is the biggest error in most tile calculators.

A 1/4 by 1/4 inch square notch for tile up to about 8 inches, a 1/4 by 3/8 inch notch for tile up to about 15 inches such as a 12 × 12, and a 1/2 by 1/2 inch notch for large-format tile of 15 inches or more. Large-format tile also needs back-buttering, a thin coat on the back of the tile, to reach full mortar contact. The trowel sets how much thinset the job uses.

Grout is a volume: it depends on the joint width, the joint depth (which equals the tile thickness), and the tile size. Bigger tile has less joint per square foot, so a 25 pound bag grouts about 366 square feet of 12 × 12 or 731 of 24 × 24 at a 1/8 inch joint, but far less of a small mosaic. This calculator uses the manufacturer volume formula, not a flat pounds per square foot.

Use unsanded grout in joints under 1/8 inch and sanded grout in joints 1/8 inch and wider, up to about 1/2 inch. Sanded grout resists cracking in a wide joint; unsanded is smoother and stays put in a narrow one. Never use sanded grout on polished stone or glass tile, even in a wide joint, because the sand scratches the surface. Many all-purpose grouts now cover the full range.

Not quite. A nominal 12 by 12 inch tile is usually about 11 and 7 eighths inches on a side, and a 24 inch tile a little under 24. The missing sliver is the grout joint the nominal size assumes. That is why you do not add a joint on top of the nominal number when counting, and why this calculator reconstructs the true footprint from the tile size and the joint you choose.

Yes. It is free, needs no signup, and runs entirely in your browser. Nothing you enter is uploaded anywhere.

No. This calculator works from an area you type in, and it sizes material, it does not lay out where the cut tiles land. To measure floor areas straight off a PDF plan to scale, so your tile, grout, and thinset come from the drawing, use Easy Takeoffs, the construction takeoff software built to measure off plans. 14-day trial, no card.