CalcArcade.

Tile Calculator

Enter the size of the room, the size of one tile and the grout joint. Add a waste allowance for cuts. You get the number of tiles to buy, and the number of boxes if you know how many tiles come in one.

Your numbers

Result

How we calculate it

Each tile covers its own size plus half the grout joint on each side, so the area per tile is (tile width + joint) × (tile length + joint). The number of tiles is the room area divided by that, plus the waste allowance, rounded up to a whole tile.

For a 10 by 12 foot room (120 square feet) with 12 inch tiles and a 1/8 inch joint, each tile covers 12.125 × 12.125 inches, which is 1.021 square feet. That is 117.5 tiles, or 129.3 with 10% waste, so you need 130. If 10 tiles come in a box, you need 13 boxes.

Assumptions and limits

  • Waste depends on the room shape and the layout. Rooms with many corners, diagonal layouts and patterns need more waste, and 10% is a common starting point.
  • The calculator treats the room as one rectangle. For an L shaped room, work out each rectangle and add them.
  • Always check the box coverage and buy from the same batch, since colors can differ between batches.

Frequently asked questions

How many tiles do I need for my floor?

Divide the floor area by the area of one tile including its joint, then add 10% or so for cuts and breakage. The calculator does this and rounds up.

How much waste should I allow for tile?

Around 10% suits a simple straight layout. Diagonal layouts, large tiles in small rooms and patterned tiles need more.

Does the grout joint make a difference?

A little. A wider joint means each tile covers more floor, so you need slightly fewer tiles. On a small floor the difference is a few tiles.

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Worked example (a fixed example using the starting numbers, it does not change as you type)

Inputs: Units = US (feet and inches); Room length (feet or meters) = 10; Room width (feet or meters) = 12; Tile width (inches or centimeters) = 12; Tile length (inches or centimeters) = 12; Grout joint (inches or millimeters) = 0.125; Waste and cuts (%) = 10.

  • Floor area 120.00 sq ft
  • Tiles without waste 118
  • Tiles needed (with waste) 130

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Last reviewed: . Formulas and assumptions are described on our methodology page. For information only; not professional advice.