Tile Calculator

Find out how many tiles you need for a floor or wall, based on your area and tile size — with waste and estimated cost included.

How to calculate how many tiles you need

The number of tiles depends on the area you are covering and the size of each tile:

Tiles needed = area ÷ area of one tile × (1 + waste %)

This calculator converts your tile dimensions from inches to square feet (width × height ÷ 144), divides your total area by that figure, adds a waste allowance, and rounds up. The same method works for both floors and walls.

How much extra tile should you buy?

LayoutRecommended waste
Straight, grid layout10%
Diagonal layout15%
Complex rooms or many cuts15–20%
Small mosaic or patterned tile15%+

Good to know

  • Keep spares. Tile dye lots vary between batches, so buy enough at once and keep a few spares for repairs.
  • Don't forget mortar and grout. Coverage depends on tile size and spacing — check the product bag.
  • Measure walls separately. For a backsplash or shower, calculate each wall as its own area and add them up.

Frequently asked questions

How many 12x12 tiles do I need for 100 sq ft?
A 12 × 12 in tile covers exactly 1 sq ft, so 100 sq ft needs 100 tiles — plus about 10% waste, which comes to 110 tiles.
How much extra tile should I buy?
Around 10% for a straight grid layout, and 15% or more for diagonal patterns, mosaics, or rooms with lots of cuts.
How do I calculate tiles for a wall?
Exactly like a floor: measure the wall height and width for the area, divide by one tile's coverage, and add waste.
Should I buy by tile or by box?
Stores sell tile by the box. Take the number of tiles here and divide by the tiles-per-box on the carton, then round up.

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