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Tile Calculator

Enter the floor or wall size, your tile size and the grout joint to see how many tiles to buy, with extra for cuts and breakage. Add the square feet per box to get a box count.

10 ft12 ft

Your measurementsWalls, floors & paint

%
10% straight lay, 15% diagonal or patterned, 15–20% L-shaped rooms
sq ft
$

What to order

  • Tiles65 tiles
  • Floor area120 sq ft
  • With 10% extra132 sq ft

What to measure

Diagram of a rectangle or square: measure the length and width
Rectangle or squareMeasure the length and width.
Diagram of a l-shape: measure the length, width, cut-out length and cut-out width
L-shapeMeasure the length, width, cut-out length and cut-out width.

How to use the tile calculator

  1. Pick a rectangle or an L-shape and enter the size. For a wall, enter its width and height.
  2. Enter the tile size and the grout joint.
  3. Set the extra for waste: 10% for a straight lay, more for diagonal, herringbone or awkward rooms.
  4. Optional: enter the square feet per box (printed on the box) and a price per square foot.

The formula

  • Area to buy = room area × (1 + waste %)
  • Each tile covers (tile length + joint) × (tile width + joint) ÷ 144 sq ft, with sizes in inches
  • Tiles = area to buy ÷ coverage per tile, rounded up
  • Boxes = area to buy ÷ square feet per box, rounded up

Worked example: 10 × 12 ft floor, 12 × 24 in tile

  • Floor: 10 × 12 = 120 sq ft; plus 10% = 132 sq ft
  • Each tile with a 3/16 in joint: 12.1875 × 24.1875 ÷ 144 = 2.047 sq ft
  • 132 ÷ 2.047 = 64.5 → 65 tiles
  • In boxes of 16 sq ft: 132 ÷ 16 = 8.25 → 9 boxes; at $2.50 per sq ft, $330.00

Tiles per 100 square feet

With 10% extra, rounded up.

Tile size Joint Tiles
3 × 6 in subway 1/16 in 854
12 × 12 in 1/8 in 108
12 × 12 in 3/16 in 107
12 × 24 in 3/16 in 54

Frequently asked questions

How many 12 × 24 tiles do I need for 100 square feet?

54 tiles with a 3/16 in grout joint and 10% extra. Each tile and its share of the joint covers about 2.05 sq ft, so 110 sq ft ÷ 2.05 rounds up to 54.

How many 12 × 12 tiles are in 100 square feet?

107 tiles with a 3/16 in joint and 10% extra, or 108 with a 1/8 in joint. With no extra and no joint it would be exactly 100.

How much extra tile should I buy?

Clé Tile recommends 10% extra for a straight lay, 15% for diagonal or intricate patterns, and 15–20% for L-shaped rooms or curved walls. Keep a few spare tiles after the job for repairs, since a later batch may not match.

How many subway tiles do I need for a backsplash?

3 × 6 in subway tile with a 1/16 in joint takes about 854 tiles for 100 sq ft, including 10% extra. Measure each wall section, add them up, and subtract large openings such as windows.

What grout joint width should I use?

Follow the tile maker's instructions. For large-format tile Daltile calls for a joint of at least 3/16 in, which is why the calculator starts there for 12 × 24 in tile. Smaller tiles often use 1/8 in, and wall tile 1/16 in.

How many boxes of tile do I need?

Divide the square feet you need, including the extra, by the coverage printed on the box, and round up. 132 sq ft of tile in boxes covering 16 sq ft is 8.25, so buy 9 boxes.

Sources

Formulas and defaults last reviewed October 30, 2026. How we check our math.