Tile Calculator

First calculate the total area to be tiled in square inches. Then calculate the area of one tile including its grout joint: (tile length + grout gap) x (tile width + grout gap) in square inches. Divide total area by tile area and round up to the nearest whole tile, then add your waste percentage. This calculator automates all of these steps.

A 10% waste factor is standard for straight-lay installations in simple rectangular rooms. Diagonal installations need 15 to 20%. Complex patterns such as herringbone or rooms with many cuts around obstacles may need 20 to 25%. Always buy at least 10% extra and keep a box of leftover tile for future repairs, as matching discontinued tile is very difficult.

The grout joint adds to the effective size of each tile when calculating coverage. A larger grout gap means slightly fewer tiles are needed, but the difference is minor for typical gap widths (1/8 to 3/8 inch). For very large tiles (24x24 inches) with a 1/16-inch rectified joint, the grout gap has negligible effect. This calculator accounts for the grout gap accurately.

The number of tiles per box varies by size and manufacturer. Large format tiles (18x18 inch or 24x24 inch) may have only 3 to 6 tiles per box. Small mosaic tiles on mesh sheets may have 1 sheet per box. Standard 12x12 inch tiles typically come 10 to 20 per box. Enter the tiles per box from your product packaging to get the box count in this calculator.

Tile installers generally tile walls before floors so that wall tile cuts fall onto the floor tile rather than onto a finished floor surface. For kitchens, the backsplash goes up after cabinets and countertops are installed. For bathrooms, the shower walls are typically tiled before the shower floor and the bathroom floor tiles are laid last. Always consult a professional installer for guidance on your specific project.