Tile Calculator

Before applying any adhesive, spend 30 minutes doing a dry layout. Snap chalk lines along both center axes of the floor and dry-lay tiles along each axis to see how the layout lands at the walls. Your goal is to have cut tiles at opposite walls that are equal in width and at least half a tile wide — narrow slivers at the walls look unprofessional and are difficult to cut cleanly on a wet saw. If the layout produces a sliver smaller than 2 inches on one wall, shift the center line by half a tile width to balance both edges.

For walls, work from the center out as well, and make sure the layout is plumb. A single off-plumb starting course will compound down the wall with every row. On shower surrounds and feature walls, center the layout on the focal point — typically the center of the shower valve wall — so that the most visible area shows full tiles. Cuts on the side walls are acceptable; cuts on the main wall are not. Taking an extra hour on dry layout before setting a single tile will save you three hours of rework later.

Straight-lay patterns with large-format tiles on simple rectangular floors can typically work with a 10% waste factor. Each wall edge requires a cut tile, but the offcut from one end of the room can often be used at the opposite end. Large tiles (18 inch and above) are more prone to cracking during cutting and handling, so use 12 to 15% even for straight layouts.

Diagonal layouts require at least 15 to 20% waste because the angled cuts at all four walls produce large triangular offcuts that cannot be reversed and reused. Herringbone patterns, Versailles patterns, and small mosaic tiles can run to 20 to 25% waste on rooms with multiple corners, obstacles, or curved elements. Always buy all tiles from the same production lot number — tile manufacturers print the lot number on the box. Color can vary measurably between production runs even within the same product line, and mixing lots on a single floor is visible when light hits the surface at a low angle.

The core formula is: Tiles = ceil(Area / Tile Area) × (1 + Waste Factor). Your surface area in square feet is divided by the face area of a single tile (length × width in feet), then the waste factor multiplier is applied, and the result is rounded up to the next whole tile. Grout quantity is calculated from the area, joint width, and tile thickness using the manufacturer's yield factor for the selected grout type.

Thinset (adhesive) quantity is estimated from the surface area and the recommended trowel notch size for your tile size — larger tiles require a larger notch to achieve the correct mortar transfer. The calculator selects the appropriate notch size based on tile dimensions. All quantities include the waste factor, so you should not add additional waste on top of the totals reported. If your project has unusual geometry — curved walls, round columns, or inset borders — add an extra 5% manually to account for the extra cuts those features require.