Tile Quantity Calculator

The tile quantity calculator finds how many tiles cover any rectangular surface, a floor, wall, backsplash, or rooftop, accounting for grout gaps, tile overlap, and a configurable waste percentage for an accurate material count.

• Area and tile dimensions. Length and width for both the surface and a single tile, in imperial (inches, feet) or metric (centimeters, meters) units. Common tile sizes include 12 by 12 inches, 6 by 24 inches, and 30 by 60 centimeters.
• Gap size. A positive value is a grout gap; a negative value is tile overlap, common for roof tiles or siding. The default is 1/8 inch, a standard grout line width.
• Waste percentage. Defaults to 10 percent, which works for standard grid layouts; diagonal, herringbone, or running bond patterns typically need 15 percent or more, since more cuts go to waste at the pattern's edges.
• Price per tile, tiles per box, and price per box. Any of these produce both a per-tile cost and a box-based cost once entered.
• Accepted formats. Fractions (3/4), mixed numbers (5 1/16), and decimals (0.75) are all accepted.

The surface divides into a grid of effective tile cells, each measuring (tile length plus gap) by (tile width plus gap). Tiles along length equals the ceiling of area length divided by (tile length plus gap); tiles along width equals the ceiling of area width divided by (tile width plus gap). Total tiles equals tiles along length times tiles along width. Tiles with waste equals the ceiling of total tiles times (1 plus waste percentage divided by 100).

An 8 by 5 foot bathroom floor tiled in 12 by 12 inch tile with a 1/16 inch grout gap needs tiles along length of the ceiling of 8 divided by 1.0052 feet (12.0625 inches), which is 8, and tiles along width of the ceiling of 5 divided by 1.0052, which is 5. Total tiles is 8 times 5, or 40, and a 10 percent waste allowance brings that to 44 tiles.

Material purchases for a wide variety of tiling projects come from the same core estimate, whether covering a small bathroom floor or an entire outdoor patio, reducing guesswork and avoiding costly over-ordering or return trips to the store.

• Bathroom Renovation: An 8 by 5 foot floor area with 12 by 12 inch tile and a 1/16 inch grout gap returns the tile count plus a 10 percent waste buffer for cuts around the toilet and vanity.
• Kitchen Backsplash: A 30 by 144 inch backsplash area in 3 by 6 inch subway tile with 1/8 inch spacing compares costs by price per tile or price per box to find the most economical option.
• Roof Tiling: A roof surface area in square meters, with a negative gap value such as -50 mm accounting for tile overlap, typically runs a 15 percent waste allowance for ridge and hip cuts.
• Outdoor Patio: A large paver installation, sized in feet with 18 by 18 inch pavers and 1/4 inch spacing, uses the box count and price per box outputs for a quick budget estimate.
• Commercial Flooring: Large office spaces or retail floors, sized in meters with 60 by 60 centimeter porcelain tile and a 2 millimeter gap, size out for contractor bids.
• DIY Wall Accent: A 10 by 8 foot feature wall in mosaic sheets or individual tiles, measured in centimeters, typically runs a 12 percent waste allowance for intricate designs or pattern matching.
• Contractor Estimation: Room dimensions from a floor plan, tested against multiple tile sizes, compare material counts and costs before options go to a client.