onlinecalculator.me

Free online tile calculator

Tile count depends on room area, tile size, grout joint width, and how much waste cuts create. This calculator combines all four factors so you order exactly enough — and a few.

Tiles needed
— tiles
Total area (with waste)
— sq ft
Extra tiles (waste buffer)
—
About this calculator

How to use

  1. Enter the room length and width in feet.
  2. Enter the tile length and width in inches.
  3. Enter the grout joint width in inches (default 0.125 in = 1/8 in).
  4. Set the waste percentage (10% for straight layouts; 15–20% for diagonal or pattern).
  5. Read the tile count, total area with waste, and extra tile buffer.

Formula

room area     = room length (ft) × room width (ft)
total area    = room area × (1 + waste% ÷ 100)
effective L   = (tile length (in) + grout (in)) ÷ 12   → feet
effective W   = (tile width (in) + grout (in)) ÷ 12    → feet
tile sq ft    = effective L × effective W
tiles needed  = ceil(total area ÷ tile sq ft)
extra tiles   = tiles needed − ceil(room area ÷ tile sq ft)

Worked example

10 ft × 10 ft bathroom, 12 × 12 in tile, 1/8 in grout, 10% waste:

room area    = 10 × 10              = 100 sq ft
total area   = 100 × 1.10           = 110 sq ft
effective L  = (12 + 0.125) ÷ 12   ≈ 1.0104 ft
tile sq ft   = 1.0104 × 1.0104     ≈ 1.0210 sq ft
tiles needed = ceil(110 ÷ 1.0210)  = 108 tiles

Buy 108 tiles. At 10 tiles per box, you’d need 11 boxes.

Notes

  • Always order tiles from the same lot number to guarantee consistent color and size.
  • Keep 5–10 extra tiles after installation for future crack or chip repairs.
  • Large-format tiles (24 × 24 in and up) typically need a 3/16 in joint and a flatter, more level substrate.

Frequently asked

How do I calculate how many tiles I need?
Divide the total area (room area × waste factor) by the area of one tile including grout. The calculator does this automatically — enter room and tile dimensions and it handles the math.
What grout joint size should I use?
Standard joints are 1/16 in (1.6 mm) for rectified tile, 1/8 in (3.2 mm) for most ceramic tile, and 3/16–1/4 in (4.8–6.4 mm) for natural stone. The default in this calculator is 1/8 in (0.125 in).
How much waste should I add for tile?
10% is standard for straight grid layouts. Add 15% for diagonal (45-degree) layouts. Add 15–20% for complex patterns like herringbone or Versailles.
What does the extra tiles count mean?
Extra tiles is the difference between the tiles you'd need without waste and the total you need with waste. These tiles cover cuts, breakage, and future repairs. Always keep leftover tiles after installation.
My tiles are sold by the box, not individually. How do I use this?
Divide the tile count by the number of tiles per box (shown on the label), then round up. For example, 87 tiles at 10 per box = 9 boxes. The calculator gives you the tile count — the box conversion is a quick division.