Tile Grid Layout Calculator
Count how many rectangular tiles fit across and down a surface as a whole-tile grid, including the grout gap between them.
How it works
Columns = ⌊(width + grout) ÷ (tile width + grout)⌋ · Rows likewise · Full tiles = columns × rows
Each tile occupies its own size plus one grout line, so the repeating cell is tile + grout wide. Because the final tile in a row has no grout after it, the width gets one grout width added back before dividing. Any space left over after the whole tiles is the edge strip you cut down to finish the row or column.
Worked example
On a 120×96-inch wall with 12-inch tiles and a 1/8-inch (0.125) grout gap, the cell is 12.125 inches. Columns = ⌊(120 + 0.125) ÷ 12.125⌋ = 9, rows = ⌊(96 + 0.125) ÷ 12.125⌋ = 7, so 63 full tiles, plus edge cuts and about 10% extra for breakage.
Frequently asked questions
Does this include cut tiles at the edges?
It counts only full, uncut tiles and reports the leftover edge gap separately. You will cut partial tiles from full ones to finish those strips, which is why buying 10% extra is wise.
Why add the grout width back before dividing?
Grout lines sit between tiles, not after the last one. A row of n tiles has n−1 grout lines, so treating the surface as one grout wider makes the simple division come out right.
How much waste should I budget?
Ten percent covers straightforward layouts; add more (15–20%) for diagonal patterns, large-format tiles, or rooms with many corners and cutouts where offcuts are harder to reuse.
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This calculator is for educational purposes. Double-check important results before acting on them.