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Tile Calculator

How many tiles and boxes to buy for a floor, shower wall or backsplash, with the grout joints counted.

Area to tile
Shape
Tile
Tile
1/8 in is 0.125; 1/16 is 0.0625; 3 mm is about 1/8 in.
%
10% for straight layouts; 15% for diagonal, herringbone or rooms with many corners.
sq ft
From the box or product page. Leave at 0 to skip the box count.
Your price
Your price
$
Leave at 0 to skip the cost estimate.
Tiles to buy 44 tiles 80 sq ft of tiling plus 10% extra: 88 sq ft.

Tiles

Area to buy, with extra
88 sq ft
Area to tile
80 sq ft
Tiles per sq ft (with joints)
0.49

Cost

How many tiles do I need?

Work out the area in square feet and add 10% for cuts. Then divide by the area one tile covers including the grout joint: (tile length + joint) × (tile width + joint) ÷ 144, in inches. A 10 × 8 ft floor in 12 × 24 in tiles with 1/8 in joints needs 44 tiles.

Worked example: a 10 × 8 ft bathroom floor in 12 × 24 in tile

  1. Area: 10 × 8 = 80 sq ft, +10% = 88 sq ft.
  2. One tile with its joint: 12.125 × 24.125 in = 292.5 sq in ÷ 144 = 2.03 sq ft.
  3. Tiles: 88 ÷ 2.03 = 43.3, so 44 tiles.
  4. Boxes: enter the square feet per box from the carton to get a box count.

Tiles per 100 sq ft by size

With 1/8 in grout joints.

Tile sizeTiles per sq ftPer 100 sq ftWith 10% extra
3 × 6 in (subway)7.52753828
4 × 4 in8.46847931
6 × 24 in (plank)0.9798108
12 × 12 in0.9898108
12 × 24 in0.495055
18 × 18 in0.444449
24 × 24 in0.252528

Sizes are nominal. Many tiles are slightly smaller than their name, so check the actual size if you need an exact count.

How much extra tile to buy

  • 10% for a straight grid in a simple room.
  • 15% or more for diagonal, herringbone or offset patterns, small rooms with many cuts, or large tiles that break easily.
  • Keep spares. Tile batches vary in color, and a few spare tiles make future repairs invisible.

Walls, showers and backsplashes

For a wall, enter its length and height. For a shower, work out each wall separately and add them, then subtract the niche or window. For a backsplash, measure the length along the counter and the height up to the cabinets, and subtract windows and outlets only if they're large.

Grout and thinset coverage depend on the product, the trowel notch and the joint width, so use the coverage chart on the bag.

Frequently asked questions

How many 12 × 24 tiles do I need for 100 sq ft?
About 50 with 1/8 in joints, or 55 with 10% extra.
How many 12 × 12 tiles are in 100 sq ft?
100 without joints, or about 98 with 1/8 in grout joints. Buy about 108 to allow 10% for cuts.
How much extra tile should I buy?
About 10% for straight layouts and 15% or more for diagonal or patterned layouts.
Do grout lines change how many tiles I need?
Slightly. Each tile plus its joint covers a little more area, so you need a few fewer tiles. With small tiles such as 3 × 6 subway, the difference is bigger.
How do I calculate tiles for a shower?
Work out each wall (width × height), add them, add the floor if you're tiling it, then add 15% because showers have many cuts.

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Sources and method

Last checked October 12, 2026. How we build and test every calculator: methodology.