80
sq ft
87
tiles
9
boxes
80
sq ft
87
tiles
9
boxes
The Tile Calculator determines exactly how many tiles you need for any floor or wall tiling project, accounting for the grout gap between tiles and a 10% waste factor for cuts and breakage. Tiles are sold individually or in boxes, and buying the right quantity — neither too many nor too few — requires precise calculation before purchasing.
Tile size dramatically affects the quantity needed. A 12×12 inch tile covers exactly 1 square foot before accounting for grout lines, while a 24×24 inch tile covers 4 square feet — meaning you need 75% fewer tiles for the same area. Large-format tiles (24×24 or larger) are popular for their seamless, modern look, but require a flatter, more carefully prepared substrate.
The grout gap — typically 1/8 inch for most floor tiles and 1/16 inch for some wall tiles — slightly reduces the effective coverage of each tile. While small, grout gaps add up: in a 200 sq ft room with 1/8" grout lines and 12×12" tiles, the grout accounts for roughly 2% of the total surface area. This calculator incorporates the grout gap into the per-tile coverage calculation for maximum accuracy.
The standard 10% waste factor covers cuts at edges, breakage during installation, and damaged tiles discovered after opening boxes. For complex patterns (diagonal, herringbone, mosaic) or irregularly shaped spaces, increase this to 15-20%.
Total Area: $$\text{Area} = \text{Length} \times \text{Width} \text{ (sq ft)}$$
Area Per Tile (including grout gap): $$\text{Tile Area} = \left(\frac{\text{Tile Length} + \text{Gap}}{12}\right) \times \left(\frac{\text{Tile Width} + \text{Gap}}{12}\right) \text{ sq ft}$$
Tiles Needed (with 10% waste): $$\text{Tiles} = \left\lceil \frac{\text{Total Area}}{\text{Tile Area}} \times 1.10 \right\rceil$$
For a 10×8 ft bathroom with 12×12" tiles and 1/8" grout:
Always round tiles needed up to a whole number. When converting to boxes, check the exact tile count per box on the product listing — this calculator assumes 10 tiles per box as a common estimate, but actual box quantities range from 5 to 20+ tiles depending on tile size and manufacturer. Save leftover tiles for future repairs — cracked or chipped tiles can be nearly impossible to match years later if the product is discontinued.
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A 48 sq ft bathroom floor using 12×12 inch tiles with standard 1/8" grout needs 52 tiles — approximately 6 boxes at 10 tiles each.
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Large-format 24×24 tiles dramatically reduce tile count. A 180 sq ft kitchen needs only 49 tiles versus 198 tiles with 12×12 format.
Standard recommendations: 1/16" for rectified (precision-cut) tiles with near-perfect edges; 1/8" for most ceramic and porcelain floor tiles; 3/16" to 1/4" for natural stone or handmade tiles with slight size variation. Larger gaps accommodate variation but collect more dirt. Consult the tile manufacturer's installation guide for specific recommendations.
Keep at least 5-10% of your purchase quantity in storage after installation. One box is the minimum recommended reserve. Tile products are frequently discontinued; matching a tile purchased 5 years ago is often impossible, making leftover tiles invaluable for future crack or chip repairs.
Yes, in many cases — provided the existing tile is firmly adhered, level, and the added height (typically 3/8 to 1/2 inch per layer) won't cause issues with doors, transitions, or appliances. Tiling over loose or cracked tile is not recommended. The surface must be clean and roughened to ensure adhesion of new thinset mortar.
Yes. Larger tiles (18×18" and above) with thinner grout lines make rooms appear larger and more seamless. Smaller tiles (mosaic, 4×4") with more grout lines can make spaces feel smaller but offer more design flexibility and are safer for wet sloped surfaces due to more grout grip. Rectangular tiles (like 12×24") can visually lengthen a space when laid in a specific direction.
Measure the backsplash area in square feet (typically width of counter × height from counter to cabinets). Subtract any outlet cutouts or windows. Apply a 10% waste factor, then divide by the tile's area to get the tile count. Subway tiles (3×6") are common for backsplashes; each tile covers 0.125 sq ft, requiring about 88 tiles per 10 sq ft with 10% waste.
Ceramic tile is made from clay fired at lower temperatures; it is less dense, easier to cut, and more affordable. Porcelain tile is fired at higher temperatures, making it denser, harder, and more water-resistant — ideal for floors, high-traffic areas, and outdoor use. Both types are calculated the same way. Porcelain is preferred for bathrooms and kitchens due to its impermeability.
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The Roboculator Team explains calculations, planning tools, and practical formulas in clear language for real-life situations.
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