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HowMuchDoINeed.fyi

Tile Calculator

How many tiles do you need?

Measurements

Units
Shape

On the box or product page — gives you a box count

Options · Grout joint 1/8 in · Extra 10%

1/16–1/8 in for most porcelain, 1/4 in for rustic tile

10% for straight layouts, 15% for diagonal or herringbone

You need

Enter length, width, tile width and tile length to see how much to buy.

Example: an 8 × 10 ft bathroom floor with 12 × 24 in tile

  1. Floor area: 10 × 8 = 80 sq ft, or 11,520 sq in.
  2. Each tile plus a 1/8 in grout joint covers 12.125 × 24.125 = 292.5 sq in.
  3. Tiles: 11,520 ÷ 292.5 = 39.4. Add 10% for cuts and breakage: 43.3, so 44 tiles.
  4. At 8 tiles per box: 44 ÷ 8 = 5.5, so buy 6 boxes.

How it's calculated

  1. Area to tile: length × width, or enter a total area.
  2. Area one tile covers: (tile width + grout joint) × (tile length + grout joint).
  3. Tiles = area × (1 + extra %) ÷ area per tile, rounded up.
  4. Boxes = tiles ÷ tiles per box, rounded up.

Assumptions

  • 10% extra by default for cuts and breakage. Use 15% for diagonal or herringbone layouts, and consider more for large-format tile, where each cut wastes more.
  • Grout joint defaults to 1/8 in (3 mm).
  • Tile size is the nominal size printed on the box.

Frequently asked questions

How much extra tile should I buy?

10% for a straight layout in a simple room, 15% for diagonal or herringbone patterns or rooms with lots of corners. Keep the leftovers: later batches rarely match exactly, so spares make repairs invisible.

Does grout width change how many tiles I need?

A little. Each joint adds to the area a tile covers, so wider joints mean slightly fewer tiles. With 12 × 12 in tile, a 1/8 in joint cuts the count by about 2%; with small tiles the effect is much bigger.

How do I measure an L-shaped room?

Split it into rectangles, work out each area (length × width), add them together and use Total area.

How many tiles come in a box?

It depends on the tile — large porcelain may come just 6–8 to a box, smaller tiles 10–15 or more. The count and square footage are printed on the box and the product page.

How do I calculate tile for a backsplash or shower wall?

Measure the width and height of each section you're tiling, multiply for the area and add them up. Subtract windows, but not outlets or small niches — the cuts around them use up tile anyway.

How do I calculate mosaic sheets?

Enter the sheet size (often 12 × 12 in) as the tile size — each sheet counts as one tile.