Tile Calculator

How it works

tile with joint = (tile length + joint) × (tile width + joint) · tiles = ⌈area ÷ tile-with-joint area × (1 + waste% + pattern%)⌉ · boxes = ⌈tiles ÷ tiles per box⌉ · grout ≈ area × (L + W) ÷ ((L + joint)(W + joint)) × joint × thickness × density · thinset bags = area ÷ bag coverage for the trowel size

Each tile takes up its own size plus one grout joint in each direction, so the area is divided by (length + joint) × (width + joint) rather than by the bare tile. That gives the exact count; the waste allowance (10% is standard) covers cuts and breakage, and the layout pattern adds more — about 5% for offset or diagonal layouts and 10% for herringbone, where many more pieces are cut. The count is rounded up to whole tiles and whole boxes, and the cost can be priced per square foot, per square meter, per tile or per box. Grout is estimated from the volume of the joints (joint width × tile thickness along every joint) and thinset from the usual trowel for the tile size. The layout check shows how many tiles fit along each wall and the size of the last cut, so you can center the layout and avoid thin slivers.

Worked example

An 8 × 10 ft floor (80 sq ft) in 12 × 12 in tile with 1/8 in joints: each tile plus joint covers 12.125 × 12.125 = 147 sq in, or 1.021 sq ft, so 80 ÷ 1.021 = 78.4 tiles. With 10% waste that is 86.2 → 87 tiles, or 9 boxes of 10. A herringbone layout adds another 10%: 78.4 × 1.20 = 94.0 → 95 tiles, 10 boxes.

Sources: TCNA Handbook for Ceramic, Glass, and Stone Tile Installation · Custom Building Products thinset coverage charts

Frequently asked questions