Tile Calculator

Calculate tiles, boxes, grout, thinset, and cost for floors and walls with pattern waste factors.

Room Length (ft)

Room Width (ft)

Tile Size

Pattern

Tile Cost ($/sqft)

Tiles Needed (10% waste)

132 tiles

14 boxes (10 per box)

Room area	120 sqft
Tile size	12" x 12" (1.00 sqft/tile)
Pattern waste	Straight lay (10%)
Tiles needed	132
Boxes	14
Grout (25 lb bags)	2 bags
Thinset (50 lb bags)	3 bags
Tile cost	$660.00
Total (tile + grout + thinset)	$765.00

info

Mike Callahan: “Diagonal and herringbone patterns waste 15-20% more tile than straight lay. Budget for it or you’ll be making two trips to the tile shop. And always buy from the same dye lot — tiles from different lots look different on the floor.”

Methodology

Tiles needed = ceil(room area / tile area x (1 + waste%)). Box count rounded up to nearest full box. Grout estimated at 1 bag (25 lb) per 100 sqft for standard grout joints. Thinset estimated at 1 bag (50 lb) per 50 sqft using a 1/4" x 3/8" square-notch trowel. Waste percentages: straight 10%, brick/offset 12%, diagonal 15%, herringbone 20%. Actual waste varies with room shape, tile size, and installer skill. Grout and thinset costs estimated at $15 and $25 per bag respectively, 2026 pricing.

Frequently Asked Questions

How many tiles per square foot?

For 12x12 tiles: exactly 1 tile per square foot. For 12x24 tiles: 0.5 tiles per square foot (each tile covers 2 sqft). For 6x24 tiles: 1 tile per square foot. For 18x18: 0.44 tiles per sqft (each covers 2.25 sqft). For 24x24: 0.25 tiles per sqft (each covers 4 sqft). Always add your waste factor on top of the net count.

How much waste for diagonal tile?

Diagonal (45-degree) layouts typically require 15% waste, compared to 10% for straight lay. The extra waste comes from cutting triangles at every wall edge — each wall line intersects tiles at an angle, producing unusable offcuts. Herringbone is worse at 20% because every row requires angled cuts and the small offcuts are rarely reusable. Experienced installers may reduce waste slightly, but always budget the full percentage.

How much thinset per square foot?

A 50 lb bag of thinset covers approximately 50 sqft when applied with a 1/4" x 3/8" square-notch trowel (the most common size for floor tile). Larger tiles (18x18 and up) require a 1/2" x 1/2" trowel, which uses more thinset — roughly 40 sqft per bag. For walls, a 1/4" x 1/4" V-notch trowel covers about 70 sqft per bag. Always back-butter large format tiles for full coverage.

How much grout do I need?

A 25 lb bag of sanded grout covers approximately 100 sqft for 12x12 tiles with 1/8" joints. Larger joints (1/4") or smaller tiles (such as mosaics) use significantly more grout — possibly 2-3x as much per square foot. Unsanded grout is used for joints 1/8" and narrower; sanded grout for wider joints. Coverage varies by tile size, joint width, and tile thickness. Check the manufacturer’s coverage chart for precise estimates.

How the Tile Calculator works

Room area is length × width in feet. Each tile’s area is its width × height in inches divided by 144, which converts square inches to square feet — a 12 by 24 inch tile covers exactly 2.0 square feet, and a 12 by 12 covers 1.0. Dividing room area by tile area gives the raw tile count before waste.

The layout pattern then sets the waste percentage: 10% for a straight lay, 12% for brick or offset, 15% for a 45 degree diagonal, and 20% for herringbone. The raw count is multiplied by that factor and rounded up, then divided by the tiles per box for your selected size and rounded up again to whole boxes.

Setting materials come off the net room area rather than the waste-adjusted area: one bag of thinset per 50 square feet and one bag of grout per 100 square feet, each rounded up. Cost adds tile (waste-adjusted square footage × your price per square foot), grout at $15 per bag, and thinset at $25 per bag.

Worked example: a 12 ft by 10 ft floor is 120 square feet. In 12 by 24 inch tile at 2.0 square feet each, that is 60 tiles net. A straight lay adds 10%, giving 66 tiles, which at 8 tiles per box is 9 boxes. The floor also takes 3 bags of thinset and 2 bags of grout. At $5 per square foot the tile runs $660, plus $75 of thinset and $30 of grout, for $765 in materials.

Frequently Asked Questions

How much extra tile should I order for a herringbone pattern?

The calculator uses 20% for herringbone, against 10% for a straight lay. Herringbone puts a diagonal cut at every wall, and the offcuts from those cuts usually cannot be reused elsewhere in the field. Diagonal at 45 degrees carries 15% and a brick or offset lay carries 12%.

How many bags of thinset and grout will I need?

The tool estimates one bag of thinset per 50 square feet and one bag of grout per 100 square feet, both rounded up. A 120 square foot floor therefore takes 3 bags of thinset and 2 bags of grout. Large-format tile and wide grout joints consume more than these averages, so treat them as a starting order rather than a final count.

Why does the box count jump when I change tile size?

Boxes hold a different number of tiles depending on size: 10 for 12x12, 8 for 12x24 and 18x18, 12 for 6x24, and 6 for 24x24. The calculator divides your tile count by the tiles per box and rounds up, so a small change in tile count can push you into another full box.

Is the waste factor applied to the tile cost as well as the count?

Yes. The cost line multiplies your square footage by the same waste percentage before applying your price per square foot, because you pay for the tile you cut up as well as the tile you set. Grout and thinset are costed off the net area, since those are consumed by coverage rather than by breakage.