Tile Calculator

How many tiles do you need? The number on the box, plus the ones you will break.

Use this free tile calculator to estimate how many tiles you need for a floor, wall, backsplash, or shower. Enter the area in square feet and the size of one tile in square feet, and get a count with a built-in 10% waste allowance for cuts, breaks, and the one tile you will drop face-down on the driveway.

Tile math is area division with a safety margin. The area part is easy; the margin is where projects go wrong. Underbuy and you discover the store's next batch is a slightly different shade. Overbuy sensibly and the leftovers fix the chip you will make in 2029.

What This Tile Calculator Does

• Calculates tiles needed from total area and tile size
• Adds 10% for waste automatically — the standard for straight layouts
• Works for floors, walls, backsplashes, showers, and patios in any square-foot measurement
• Gives you a number to compare against tiles per box so you buy whole boxes, not hopes

How to Use the Tile Calculator

Inputs:

• Area — the surface to tile in ft² (length × width; subtract large openings like a tub or a vanity if it sits on the subfloor)
• Tile Size — area of one tile in ft². A 12"×12" tile = 1 ft² (default); 12"×24" = 2 ft²; 6"×6" = 0.25 ft²; 3"×6" subway = 0.125 ft²

Steps:

1. Measure the area: length × width in feet. For L-shaped rooms, split into rectangles and add
2. Convert your tile's dimensions to ft²: (inches × inches) ÷ 144
3. Enter both and click Calculate
4. Divide by tiles-per-box on the packaging and round up to whole boxes

How the Calculation Works

Tiles = ⌈ (Area × 1.10) ÷ Tile Size ⌉ Tile Size (ft²) = (width in × length in) ÷ 144

• 10% waste suits straight (grid) layouts. Use 15% for diagonal or herringbone patterns, and 15–20% for rooms with many corners, niches, or large-format tile
• Grout lines are ignored — with a typical 1/8"–3/16" joint the difference is a couple of percent, well inside the waste margin
• Result is rounded up; you cannot buy 0.6 of a tile, though you will certainly cut one

Worked Example: 8 ft × 10 ft bathroom floor, 12"×24" tiles

1. Area = 8 × 10 = 80 ft²
2. Tile size = (12 × 24) ÷ 144 = 2 ft²
3. Tiles = ⌈80 × 1.10 ÷ 2⌉ = ⌈44⌉ = 44 tiles
4. Boxes hold 8 → 44 ÷ 8 = 5.5 → 6 boxes (48 tiles). The 4 spares are your insurance policy. Store them somewhere you will remember, which rules out the garage.

Tips (From People Who Have Made These Mistakes)

• Buy all boxes from the same lot/dye number and check it on every box — shade variation between lots is real and permanent
• Large-format tile (24"+ ) wastes more per cut. Bump waste to 15%
• Also budget thinset (~50 lb bag per 40–50 ft² for 12" tile), grout, spacers, and a wet saw rental. The tile is rarely the biggest surprise
• Tiling a wall? Measure each wall separately and subtract windows/doors — then still round up

Frequently Asked Questions

Mini Roast Disclaimer

We roast the number, not you. Your layout is fine. Your "I don't need to rent a wet saw" plan is the part we are worried about.

Reality Check

The estimate assumes a flat, rectangular area and a straight layout. Herringbone, diagonals, borders, niches, and out-of-square walls all eat more tile. Measure twice, add the right waste factor, and buy from one lot. The most expensive tile is the box you have to hunt down after the store sells out.