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- Tiles needed = area ÷ area of one tile, including the grout line.
- Add about 10% for cuts and breakage, or 15% for a diagonal layout.
- An 80 sq ft floor with 12 inch tiles and 1/8 inch grout needs 87 tiles with 10% extra.
- Round up, and buy a spare box if the style could be discontinued.
How to use the tile calculator
Enter the area
Type the length and width of the floor or wall in feet, or choose the area option if you already know it.
Enter the tile size
Type the tile length and width in inches and the grout line width. 1/8 inch is 0.125.
Set the extra
Leave 10% or change it. Use more for diagonal patterns, small rooms and natural stone.
Read the result
You get the tile count with and without waste. Add tiles per box and a price per tile to see boxes and cost.
How to calculate how many tiles you need
Each tile covers its own size plus half a grout line on every side, so the real coverage is the tile plus the grout line in both directions. Divide the area to cover by that coverage, add your waste allowance and round up.
Tile count
Coverage per tile = (tile length + grout) × (tile width + grout) ÷ 144 (sq ft)
Tiles = area ÷ coverage per tile
With waste = tiles × (1 + waste %), rounded up
Boxes = tiles with waste ÷ tiles per box, rounded up
144 square inches make one square foot.
Worked examples
An 80 sq ft floor with 12 inch tiles
10 ft by 8 ft, 1/8 inch grout and 10% waste.
You will buy 90 tiles in 9 boxes.
The same floor with 12 × 24 inch tiles
Same area, 1/8 inch grout and 10% waste.
Bigger tiles mean fewer to buy and fewer grout lines.
No grout lines
100 sq ft with 12 inch tiles, no grout and no waste.
Each tile covers exactly 1 square foot.
How much extra to buy
Common waste allowances
Rules of thumb.
Ask your tile supplier for advice on your pattern.
Where a tile calculator helps
Floors
Find the number of tiles for a kitchen, bathroom or entry. Measure the room with the square footage calculator.
Walls and backsplashes
Estimate tile for a shower or kitchen wall.
Budgeting
Turn a tile count and a price into a material cost.
Ordering boxes
Round up to whole boxes so you do not run short.
Tile color can vary slightly between production batches, so buy all your tiles at once and keep a few spares for repairs. Tile sizes can differ slightly from their label, so check the actual size on the box. This is an estimate, so confirm quantities with your supplier before you order.
Tile calculator FAQ
How many tiles do I need for 100 square feet?
With 12 inch square tiles and no grout, you need 100. With 1/8 inch grout and 10% waste it is about 108.
How much grout width should I use?
1/8 inch is common for floor and wall tile. Use the width recommended for your tile and grout type.
How much extra tile should I buy?
About 10% for a straight layout and 15% for diagonal layouts or rooms with many cuts.
Do I include grout lines in the calculation?
Yes. The tile plus the grout line is what covers the area, so including it gives a more accurate count.
How do I measure an L-shaped room?
Split it into rectangles, find each area and add them, or use the area option after measuring with the square footage calculator.
How do I calculate tile for a wall?
Multiply the wall height by its length for the area, subtract windows and doors, then use the same tile calculation.