Tile Calculator

How to use this tile calculator

What this calculator does

This calculator estimates how many rectangular tiles and full boxes are needed to cover a rectangular floor or wall. It includes the grout-joint width, a waste allowance, box rounding, and a simple material-cost estimate. It is useful for early purchasing and budget checks, but it does not design a tile pattern, account for every doorway or niche, calculate mortar or grout quantities, or replace the layout judgment of an experienced installer.

When to use it

Use it when pricing a bathroom floor, planning a kitchen backsplash, comparing tile formats for the same room, or checking whether leftover unopened boxes provide enough reserve for future repairs. For field installation guidance and recognized tile-industry resources, consult the Tile Council of North America resource center.

How to calculate

1. The calculator opens with a complete demonstration: a 12 ft by 10 ft surface, 12 in by 12 in tiles, a 1/8 in grout gap, 10% waste, 20 tiles per box, and a $42.50 box price. The example results and Excel workbook are ready immediately.
2. Replace Area length and Area width with the measured rectangular dimensions of the surface.
3. Enter the nominal Tile length, Tile width, and Grout gap from the selected product and layout plan.
4. Set the Waste factor, then enter Tiles per box and Price per box.
5. Read the live results and quantity table. Select Download Excel to save the current assumptions and outputs. Reset clears the demonstration and results; Excel remains unavailable until every required field again contains a complete valid value.

Input guide

Area length and Area width are required positive decimal measurements in feet. Values such as 12 and 10 define a 120 sq ft rectangle. Increasing either dimension raises the surface area and normally raises the tile and box counts. Measure the actual tiled plane rather than the room's outside dimensions, and separate irregular spaces into rectangles before adding their estimates.

Tile length and Tile width are required positive decimal dimensions in inches. The example uses 12 by 12. Larger tiles cover more area per piece, but the nominal size printed on a box may differ slightly from the actual manufactured size. Use one consistent size basis and do not enter feet in these fields.

Grout gap is a required nonnegative decimal width in inches; 0.125 represents 1/8 in. The calculator treats tile size plus joint width as the repeating layout module, so a wider joint modestly reduces the tile count for the same surface. Do not use a negative overlap. Joint selection should follow the tile, substrate, pattern, and manufacturer instructions; the Ceramic Tile Education Foundation overview of installation standards explains why standardized practices matter.

Waste factor is a required percentage from 0% to 100%. The example uses 10%. Higher waste increases the loose-tile requirement and can push the purchase into another box. Straight layouts in simple rooms may need less reserve than diagonals, complex patterns, fragile material, shade matching, or rooms with many cuts. Waste is an allowance, not a guarantee.

Tiles per box is a required positive whole number, such as 20. Copy it from the packaging for the exact size and series. A common mistake is entering square feet per box instead of pieces per box. Price per box is a required nonnegative U.S.-dollar amount such as $42.50. It drives only the material-cost result and excludes sales tax, delivery, trim, setting materials, substrate preparation, tools, and labor.

Output guide

Boxes to buy is the primary whole-box purchase count after waste and package rounding. Tiles before waste is the rounded-up layout count based on the repeating tile-and-gap module. Tiles including waste applies the percentage allowance and rounds up to a whole tile. Tiles purchased multiplies boxes by tiles per box, so it can exceed the waste-adjusted need. Estimated material cost multiplies boxes by box price. Surface area is the exact rectangular area entered. Purchased coverage is the nominal tile-and-gap module area represented by all purchased pieces. The summary pills repeat surface area, waste, and box count from the same model.

The Quantity breakdown table shows three stages: calculated layout, waste-adjusted planning quantity, and whole-box purchase quantity. Its tile and equivalent-area columns are estimates rather than a cut plan. Zero waste is valid, but a zero dimension, zero box quantity, malformed number, negative value, or value outside the supported range is rejected.

Worked example

For the startup example, the surface is 12 × 10 = 120 sq ft. A 12 in tile with a 0.125 in joint creates a 12.125 in by 12.125 in repeating module, or about 1.0209 sq ft. Dividing 120 by that module and rounding up gives 118 tiles before waste. Applying 10% and rounding up gives 130 tiles. At 20 tiles per box, 130 ÷ 20 rounds up to 7 boxes, so 140 tiles are purchased. At $42.50 per box, the estimated material cost is exactly $297.50.