Tile Calculator

Estimate tiles and whole boxes for floors or walls, using rectangular surfaces, grout spacing and one clearly applied waste allowance.

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How to Use the Tile Calculator

Choose floor or wall mode and imperial or metric units. Add nonoverlapping surfaces. Imperial surface dimensions are feet and tile/grout dimensions are inches; metric surfaces are meters, tiles centimeters and grout millimeters. Enter waste once, then choose tiles per box or box face-area coverage. Optionally price individual tiles or whole boxes.

Formula and Explanation

Effective module area = (tile length + joint) × (tile width + joint), in surface area units
Raw tiles = total surface area / effective module area
Purchase tiles = ceil(raw tiles × (1 + waste / 100))
Boxes by count = ceil(purchase tiles / tiles per box)
Boxes by coverage = ceil(purchase tiles × tile face area / face-area coverage per box)

The effective module includes repeating grout joints, while box coverage uses actual tile face area excluding grout. That distinction avoids treating joint gaps as physical tile coverage inside a box. Waste is applied once before whole-tile rounding; it is not added again when rounding boxes. Box purchases can supply more tiles than the required count. Loose-tile pricing and whole-box pricing are alternative purchase scenarios.

An area-based estimate is not an exact cutting layout. Perimeter grout, edge cuts, patterns, tile orientation, irregular surfaces and product tolerances can change quantities. Supply usable face-area coverage for box coverage, not a grout-included installed area. Adhesive, grout volume, substrate preparation, labor and delivery are excluded. Floor and wall mode changes the project label, not the area formula.

Worked Example

A 12 × 12 ft floor has 144 sq ft. Tiles measuring 11.5 × 11.5 inches with 0.5-inch joints form a 1 sq ft module, so 10% waste requires 159 tiles. At 10 tiles per box, buy 16 boxes supplying 160 tiles. If a box costs $25, the estimate is $400. In metric units, a 3 × 4 m wall with 29.5 × 29.5 cm tiles and 5 mm joints has 0.09 m² modules; 10% waste requires 147 tiles.

Frequently Asked Questions

Does waste get added twice when buying boxes?

No. Waste is applied once to the raw tile estimate. The calculator rounds up tiles and then rounds the purchase into boxes without applying a second waste percentage.

What coverage should I enter per box?

Use the area of tile faces supplied in a box, excluding grout. The calculation compares that value with the face area of the required whole tiles. Installed coverage including joint gaps is a different measure.

Why does grout spacing reduce the tile estimate?

Grout adds to the effective repeating tile module, so fewer modules cover the same area. This is an area approximation, not an exact model of every edge joint or cut.

Can I combine floors and walls?

You can total rectangular surfaces that share tile size, joints, waste and box settings. Use separate calculations for surfaces with different products or installation allowances.