TAHA Engineering Toolsby TAHA Knowledge Lab

Civil & Construction

Tile Calculator

Number of tiles and boxes for a floor or wall, including grout joints and wastage.

Inputs

Calculate from
Rectangular surface covered with a grid of tiles separated by grout joints, with surface length and width, tile length and width, and the joint marked.surface lengthwidthtile lengthgrout joint
Surface length × width is covered by tiles. Each tile occupies its own size plus one grout joint in each direction, so area per tile = (tile length + joint) × (tile width + joint). Diagram not to scale.

For example 2 identical walls.

Spacer size. Enter 0 to ignore joints.

For cuts and breakage. Diagonal and complex layouts need more. The value shown is an example — use your own.

Optional — from the box label.

Result

Tiles to buy (with wastage, rounded up)
37tiles
Boxes to buy
10boxes
Tiles needed (before wastage)
33.0025tiles
Surface area
12
Area covered by one tile + joint
0.363609

The surface of 12 m² needs about 33.0025 tiles. With 10% wastage, buy 37 tiles (10 boxes).

Educational estimate — check the assumptions below.

About this calculator

Find how many tiles to buy for a floor or wall. Enter the surface size (or its area), the tile size and the grout joint, then add a wastage allowance for cuts and breakage. If you enter the number of tiles in a box, the calculator also tells you how many boxes to buy.

Formula

Area per tile = (tile length + joint) × (tile width + joint)

Tiles = Surface area ÷ Area per tile    To buy = ⌈ Tiles × (1 + wastage) ⌉

Boxes = ⌈ Tiles to buy ÷ Tiles per box ⌉

Each tile is given one joint on its length and one on its width, so joints are not counted twice. ⌈ ⌉ = round up.

Worked example

Floor 4 m × 3 m, 600 × 600 mm tiles, 3 mm joints, 10% wastage, 4 tiles per box.

  • Area = 12.00 m²; area per tile = 0.603 × 0.603 = 0.3636 m²
  • Tiles = 12 ÷ 0.3636 = 33.0 → with 10%: 36.3 → buy 37 tiles
  • Boxes = 37 ÷ 4 = 9.25 → 10 boxes

Assumptions and limitations

  • A simple rectangular layout. Pattern (diagonal, herringbone), room shape, cuts at edges and around fittings, and breakage all affect the real number.
  • Buy all tiles from the same batch (shade/calibre) and keep some spares for future repairs.
  • Skirting tiles, adhesive and grout quantities are not included.

References

  • Standard tile-quantity estimating using the tile + joint module.