Interior

Tile Calculator: Tiles, Grout and Thinset

Get tile count, boxes, grout and thinset for a floor, backsplash or shower wall — with the waste factor set by your layout, not a guess.

Your measurements

Tiles to buy

93tiles

12 boxes — covers 185 sq ft including 10% waste

Area to tile
168 sq ft
With waste allowance10% for a straight layout
185 sq ft
Boxes to buy15.5 sq ft per box
12
Grout1 × 25 lb bag at a 0.125" joint
15.7 lb
Thinset mortar~45 sq ft per bag at the notch size this tile needs
5 × 50 lb bags
  • Large-format tile needs a large-notch trowel and near-total mortar coverage on the back, which is why it eats far more thinset per square foot than small tile.
  • Keep at least one full box back after the job. Tile runs are dyed in batches and an exact match years later is unlikely.

How this is calculated

  • Area is length × width, then multiplied by a waste factor set by the layout: 10% straight, 12% offset, 15% diagonal, 20% herringbone. The pattern decides how many perimeter cuts produce unusable offcuts.
  • Tile count is the padded area divided by the face area of a single tile. Boxes are the padded area divided by the coverage printed on the box.
  • Grout uses the standard industry formula — ((L + W) ÷ (L × W)) × joint width × tile thickness × 14.5 pounds per 100 sq ft, assuming a 3/8 in tile.
  • Thinset coverage per 50 lb bag is set by the trowel notch the tile size demands: roughly 90 sq ft for small tile, 65 for 12 in, and 45 for large format 18 in and above.

Quantities are rounded up, because materials are sold in whole units and a second trip costs more than a spare box. Cost figures are typical US ranges and are not a quote — always price against your own supplier.

Frequently asked questions

How much extra tile should I buy?

10% over the measured area for a simple straight layout, 15% for diagonal, and 20% for herringbone. Add a further 5% if the room has lots of jogs, niches or a curved edge — every one of those is a cut that can go wrong.

How much grout do I need for 100 square feet?

It depends far more on tile size than on area. 100 sq ft of 2 in mosaic with a 1/8 in joint takes roughly 40 lb of grout; the same 100 sq ft in 24×24 in tile takes under 5 lb. Small tiles mean vastly more joint length per square foot.

How many bags of thinset for a tile floor?

A 50 lb bag covers about 90 sq ft of small tile, 65 sq ft of 12 in tile, and only 45 sq ft of large-format tile, because bigger tile requires a deeper trowel notch and full back-buttering.

Know the quantities. Now see the room.

You have the numbers for the job. Upload a photo of the room and see what it looks like finished, in any style, before you buy a single box.

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