MaterialSum

Tile Calculator

Enter your room size and tile size to see exactly how many tiles — and boxes — to buy, including grout gaps and cutting waste.

Dimensions
ft
ft
in
in
in
Material & Waste
ft²
Optional Cost
Enter your measurements above to see results.

How to use the Tile Calculator

  1. Measure the area you are tiling (length × width, or total area).
  2. Enter your tile dimensions and the grout gap you plan to use.
  3. Keep the 10% waste allowance for cuts and breakage; use 15% for diagonal layouts.
  4. Enter box coverage (printed on the box) to convert tiles to boxes.

Formula & methodology

Effective tile size = (tile length + grout gap) × (tile width + grout gap). Tiles = Area ÷ effective tile area × (1 + waste). Boxes = tiles ÷ tiles per box, rounded up.

Example

A 10 ft × 10 ft floor with 12 in × 12 in tiles and a ⅛ in grout line: each tile plus gap covers ~1.02 ft², so you need ~98 tiles exact — buy 108 with 10% waste (11 boxes at 10 ft² each).

Related calculators

Shower Tile CalculatorBuilt for showers: multiple walls, a floor, and a door opening to subtract — so your tile count is actually right.Ceiling Tile CalculatorEnter your room size and panel format to find how many ceiling tiles — and boxes — to order for a suspended grid.Paint CalculatorEnter your wall area and number of coats to see how much paint to buy — no half-used cans, no second trip to the store.

FAQ

How much extra tile should I buy?

Add 10% for straight layouts and 15% for diagonal or herringbone patterns. Keep leftover boxes unopened for future repairs.

Does grout gap change the tile count?

Slightly — wider joints mean each tile effectively covers more area. The calculator adds the gap to both tile dimensions automatically.

How do I calculate boxes of tile?

Boxes state coverage in square feet. Divide your total area (with waste) by the coverage per box and round up — the calculator does this for you.

Should I tile floor or walls first?

Walls first is the common pro sequence: cuts at the floor line get hidden by floor tile. Always dry-lay a few rows first.