Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Calculate how many tiles you need from a floor or wall area and a specific tile's real length and width.
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Tile comes in dozens of standard sizes -- 12x12in, 18x18in, 12x24in "plank" tile, small mosaics, and more -- and the number of tiles a given area needs depends entirely on which size you've chosen. This calculator uses your tile's actual footprint, not a generic assumption, so the count matches the product you're actually buying.
Enter your floor or wall area in square feet, then your tile's length and width in inches. A waste allowance (10% is a common default) accounts for cuts at edges, corners, and breakage during installation -- diagonal layouts or small/oddly-shaped rooms typically need more waste, not less.
Tile Coverage (sqft) = (Length in × Width in) ÷ 144
Tiles Needed = (Area ÷ Tile Coverage) × (1 + Waste Factor), rounded up
The result is always rounded up to a whole tile, since a fraction of a tile still means buying a full one.
Once you know your tile count, use the Tile Cost Calculator to turn it into a material and labor cost estimate.
For a simple rectangular room, multiply length by width in feet. For an L-shaped or irregular room, split it into rectangles, calculate each one, and add them together. Do not subtract small items such as a toilet base or a vanity that sits on the floor unless you are certain the tile will not go beneath them. For walls, measure the height and width of each wall section and subtract large openings like windows or doors only if tile will not continue around them.
Take a bathroom floor of 64 square feet tiled with 12 by 24 inch tiles and a 12 percent waste allowance (hypothetical numbers). Each tile covers 288 divided by 144, which is 2 square feet. Raw count is 64 divided by 2, or 32 tiles. With 12 percent waste the count is 35.84, which rounds up to 36 tiles. If you switch to 6 by 6 inch tiles the coverage is only 0.25 square feet and you would need 256 raw tiles, roughly 287 with the same waste. The tile size makes an enormous difference in the count.
The formula uses the nominal tile size, and it does not add the width of grout joints. On a large floor with wide grout lines, the true count may be slightly lower than the calculation, because the grout space adds to each tile's footprint. This effect is usually small, and the waste allowance normally absorbs it. If you are using very small mosaic tiles sold on mesh sheets, it is often easier to calculate by the sheet: enter the sheet's total length and width as the tile size.
The calculator assumes a uniform tile size and does not model complex layouts such as a border, a feature strip, or a mix of two sizes. If your design has these, calculate each zone separately and add the results. It also assumes tile edges are flush, so a rectified tile with tight joints and a rustic tile with wide joints are treated the same way.
10% is a common default for a simple grid layout in a rectangular room. Diagonal layouts, herringbone patterns, small rooms, or rooms with many corners often need 15-20% instead.
Always round up -- a partial tile still requires buying a full one, and running short mid-installation risks a dye-lot mismatch if you have to reorder.
Not explicitly -- grout lines are thin enough that the standard waste allowance typically absorbs their effect on tile count for most tile sizes.
Check how many tiles or how many square feet are in a box on the packaging, then divide your tile count by that number and round up to a whole box.
Use the nominal tile size printed on the product. The calculator does not add grout joints, and the waste allowance generally covers the minor difference.
Yes. Measure the backsplash area in square feet, enter your tile dimensions, and consider a slightly higher waste allowance because of the many small cuts around outlets and edges.
Divide it into rectangles, add up their areas, and enter the combined total. Irregular rooms usually justify a higher waste percentage.