Tile Calculator

What is a tile calculator?

A tile calculator tells you how many tiles to buy to cover a floor of a given size. Instead of laying tiles out on paper and counting, you enter the floor area in square feet and the dimensions of one tile in inches, and the calculator returns the number of tiles you need.

It is the starting point of any tiling job: knowing the tile count lets you price the order, buy in a single delivery, and avoid both running short halfway through and paying for boxes you never open.

How does it work?

The idea is simple — divide the area you want to cover by the area of one tile, then round up because you cannot buy part of a tile.

Tile sizes are quoted in inches but floor area is usually in square feet, so the two have to be brought into the same units first. One square foot is $12 \times 12 = 144$ square inches, so a tile that is $w$ inches wide and $h$ inches tall covers:

The number of tiles is then the floor area divided by the area of one tile, rounded up to the next whole tile:

The ceiling matters: even if the division comes out to 99.2 tiles, you need 100, because that last fractional tile still has to cover a real piece of floor.

Worked examples

100 sq ft with 6-by-6-inch tiles. Each tile covers $6 \times 6 / 144 = 0.25$ sq ft. Dividing the floor by the tile gives $100 / 0.25 = 400$, so you need 400 tiles.

120 sq ft with 12-by-12-inch tiles. A 12 × 12 tile is exactly one square foot, so the count equals the area in square feet: $120 / 1 = 120$, or 120 tiles.

200 sq ft with 12-by-24-inch tiles. Each tile covers $12 \times 24 / 144 = 2$ sq ft, so you need $200 / 2 = 100$ tiles. Larger tiles cover more ground, so the count drops — 100 tiles here.

Practical notes

• Buy extra for waste. The count above is the bare minimum with no allowance for cuts. Add roughly 10% for edges, corners, and breakage, and 15% or more for diagonal or herringbone layouts where off-cuts are larger. On the 400-tile floor, that means picking up about 440 tiles.
• Subtract fixed obstacles, or don’t. This estimator covers the full area you enter. If a large island or built-in takes up floor, subtract its square footage before entering the area; for small fixtures it is usually safer to tile underneath and ignore them.
• Grout and spacers are separate. The tile count assumes tiles butted edge to edge; the small grout gap between tiles is negligible for counting purposes, but the grout, spacers, and adhesive are separate purchases.
• Mind the room shape. Long, narrow rooms and rooms with many cuts waste more tile than a simple rectangle of the same area, so lean toward the higher end of the waste allowance.

Pair this with a square footage calculator to work out the floor area from its length and width, a paver calculator for outdoor patios and walkways, or a concrete block calculator when the project moves from floors to walls.

Frequently asked questions

Do I enter tile size in inches or feet? Inches. Most tiles are sold by their inch dimensions (12 × 12, 18 × 18, 6 × 24), so the calculator takes inches and converts internally using the fact that one square foot is 144 square inches.

Why does the result round up? Because a partial tile still covers real floor. If the math gives 99.2 tiles, the leftover 0.2 of a tile is a sliver of floor that must be covered, so you round up to 100.

How much extra should I buy? Around 10% over the calculated count for a straight layout, more for diagonal or patterned designs. Keeping a few spare tiles from the same batch is also useful for repairs later, since dye lots vary between production runs.