ClutchCalcs

Construction

Tile Calculator

Tiling a bathroom floor, kitchen backsplash, shower walls, or patio? Walking into the tile store with the wrong count is how you end up either short on tiles two days into the job (and the store's out of that batch — dye lots vary) or with five extra boxes at $80 each. This calculator takes your floor dimensions, tile dimensions, and a waste factor (10% for simple rectangular layouts, 15% for diagonals or patterns, 20% for complex) and returns the exact tile count to buy. Round up to nearest box at the store — having 5% leftover for future repairs is cheaper than a second batch later.

Enter floor and tile dimensions.

Waste factors by layout pattern

  • 10% — simple grid layout, rectangular room, small-to-medium tiles (under 12" square).
  • 12-15% — grid layout in non-rectangular rooms (L-shape, multiple closets, kitchen with islands). Or 18"+ large-format tiles where each cut wastes more.
  • 15-20% — diagonal layout (45° rotation), herringbone, basket weave, or any pattern that requires angled cuts at edges.
  • 20-25% — complex patterns (Versailles, pinwheel, octagon+dot), or rectangular tiles in offset/brick pattern at small scale (subway).
  • 25%+ — unusual shapes (hexagon, fish scale), salvaged or expensive specialty tile where you can't run short.

Worked example

10x12 kitchen floor with 12"x12" porcelain tile, 10% waste. Floor area: 120 sq ft = 17,280 sq in. Tile area: 144 sq in each. Base count: 120 tiles. With 10% waste: 132 tiles. At ~10 tiles per box (10 sq ft/box for 12" tile), 14 boxes. Order 14 boxes for safety margin.

40 sq ft subway tile backsplash (3"x6" tiles), 15% waste for offset brick pattern. Tile area: 18 sq in. Base count: 320 tiles. With 15% waste: 368 tiles. Round up to nearest 50 = 400 tiles to handle pattern cuts cleanly.

How to use this calculator

  1. Floor length and width in feet.
  2. Tile length and width in inches.
  3. Waste factor: 10% for simple layouts, 15-20% for patterns.
  4. Output: total tile count needed, floor area, tile size.
  5. For wall tile (backsplash, shower): same math. Use wall area in sq ft + tile dimensions.
  6. For irregular rooms: break into rectangles, calculate each, add tile counts.

Common scenarios

Master bathroom floor 8x6, 12x24 large-format porcelain, 15% waste. 48 sq ft = 6,912 sq in. Tile: 288 sq in. Base: 24 tiles. With waste: 28 tiles. At 8 tiles/box: 4 boxes.

Kitchen backsplash 30 sq ft, 3x6 subway, 15% waste. 30 sq ft = 4,320 sq in. Tile: 18 sq in. Base: 240 tiles. With waste: 276 tiles. Typical pack of 80 tiles: 4 packs.

Shower walls + floor combined 90 sq ft, mixed tile sizes. Calculate walls and floor separately, sum quantities. Floor often gets larger tiles (12x12 or 18x18) for fewer grout lines; walls use 6x6 or subway for vertical visual interest.

FAQ

Why so much waste? +
Cuts at walls, around obstacles (toilet, vanity, doorways), broken tiles from shipping, and future repair stock. 10% is the floor for a simple rectangular layout; complex layouts can require 25%+. The cost of over-buying ($50-200 in extra tiles) is much less than the cost of running out and re-doing trips.
What about grout? +
Separate purchase. Grout consumption depends on tile size, joint width, and depth. For most floor tile: 1 lb of grout per 8-10 sq ft. For mosaics: 1 lb per 3-4 sq ft. Buy a 25-lb bag for 100-200 sq ft of standard tile.
Should I buy by the box or by the piece? +
Tile is sold by the box, with each box covering a stated sq ft. Calculate sq ft, add waste, then check the box's sq ft coverage — you'll usually round up by box. Saves the hassle of counting individual tiles and ensures you have full boxes of consistent dye lot.
What's a "dye lot"? +
Each production batch of ceramic or porcelain tile has slight color variation. Tiles from different lots may not match perfectly. Always order all your tile in one batch + 5-10% extra to keep in case of future repairs. Stores can't always match dye lots later.
How much extra should I store for future repairs? +
5-10% over what you actually install. Keep them dry, away from temperature extremes. Label the box with location/date so future you (or future homeowner) can match the original.
What thickness of tile for floors? +
Standard porcelain floor tile: 5/16" to 3/8". Outdoor patio tile: 1/2" or more. Large-format (24" or larger): often 5/16" with backer board to prevent flex. Match thickness to existing flooring height when transitioning to other rooms.
Porcelain or ceramic? +
Porcelain: denser, harder, lower water absorption, more durable, better for floors, often 2-3x cost of ceramic. Ceramic: cheaper, works on walls fine, fine for low-traffic floors, less durable than porcelain. For bathroom/kitchen floors: porcelain is the standard choice.
What's the difference between rectified and pressed-edge tile? +
Rectified: cut precisely to size after firing; allows very tight grout joints (1/16"-1/8"). Pressed-edge: slight size variation between tiles; requires wider grout joints (1/8"+). Both work fine — rectified is more modern and looks cleaner but costs more.