Tile Calculator — Free Online Tile Estimator

How to Use the Tile Calculator

1. Enter the area to tile: Measure the floor or wall area you plan to tile and enter it in square feet. For rectangular rooms, multiply the length by width. For L-shaped or irregular areas, break them into rectangles, calculate each area, and add them together. Subtract any areas that will not be tiled, such as islands, cabinets, or tub surrounds.
2. Enter tile dimensions: Input the width and length of your selected tile in inches. Check the tile box or product listing for exact dimensions. Common floor tile sizes include 12x12, 12x24, 18x18, and 24x24 inches. Common wall tile sizes include 3x6 (subway), 4x4, 6x6, and 4x12 inches. Tile dimensions affect the number of individual tiles needed and the amount of grout required.
3. Set the grout gap width: Enter the grout joint width in inches. The default is 1/8 inch (0.125), which is standard for most ceramic and porcelain tiles. Use 1/16 inch for rectified porcelain with minimal grout lines, or 3/16 inch for natural stone and rustic-style tiles. The grout gap affects both tile count and grout quantity.
4. Adjust box size, price, and waste: Enter the number of tiles per box and the price per box from your supplier. Adjust the waste factor based on your layout pattern: 10% for straight grid layouts, 15% for diagonal layouts, and 20% for complex patterns like herringbone or chevron. The calculator provides individual tile count, boxes to purchase, grout weight, thinset bags, and estimated tile cost.

All results update instantly as you modify any input. Use the calculator to compare costs between different tile sizes and layouts before purchasing.

Tile Calculation Formula

Variables Explained

• Tile Area: The coverage of one tile including its share of the grout gap, converted from square inches to square feet by dividing by 144. The grout gap is added to both dimensions because each tile must account for half of the gap on all four sides.
• Waste Factor: A multiplier applied to the total area to account for cuts, breakage, and fitting. The standard 1.1 (10%) waste factor means ordering 10% more tiles than the exact calculated quantity. Complex layouts and irregular room shapes require higher waste factors.
• Grout Estimate: Calculated at approximately 0.5 pounds per square foot for standard tile sizes. This provides a reliable estimate for ordering purposes, though actual usage varies with tile size and gap width.
• Thinset Estimate: Based on the standard coverage rate of 95 square feet per 50-lb bag using a 1/4-inch square-notch trowel. Larger tiles requiring larger trowel notches will need more thinset per square foot.

Step-by-Step Example

Suppose you are tiling a 10 x 12 foot bathroom floor (120 sq ft) with 12x12 inch tiles, 1/8 inch grout gaps, 10 tiles per box at $30 per box, and a 10% waste factor:

1. Calculate tile area: ((12 + 0.125) x (12 + 0.125)) / 144 = 1.018 sq ft per tile
2. Calculate adjusted area: 120 x 1.1 = 132 sq ft
3. Calculate tiles needed: 132 / 1.018 = 130 tiles
4. Calculate boxes: 130 / 10 = 13 boxes
5. Estimate grout: 132 x 0.5 = 66 lbs
6. Estimate thinset: 132 / 95 = 2 bags
7. Tile cost: 13 x $30 = $390

This bathroom floor requires 13 boxes of tile ($390), 66 pounds of grout, and 2 bags of thinset mortar. The total material cost including grout (about $25) and thinset (about $30) would be approximately $445.

Practical Examples

Example 1: Patricia's Kitchen Floor

Patricia is retiling her 180 square foot kitchen floor with 12x24 inch porcelain tiles. The tiles come 6 per box at $45 per box. She uses a 1/8 inch grout gap and 10% waste factor:

• Tile area: ((12 + 0.125) x (24 + 0.125)) / 144 = 2.026 sq ft per tile
• Adjusted area: 180 x 1.1 = 198 sq ft
• Tiles needed: 198 / 2.026 = 98 tiles
• Boxes: 98 / 6 = 17 boxes
• Grout: 99 lbs, Thinset: 3 bags
• Tile cost: 17 x $45 = $765

Patricia also orders 2 extra boxes as repair spares, bringing her total to 19 boxes ($855). The 12x24 format gives her kitchen a modern, spacious look with fewer grout lines than smaller tiles.

Example 2: James's Bathroom Renovation

James is tiling the floor (60 sq ft) and shower walls (80 sq ft) in his master bathroom. He uses 6x6 inch ceramic tiles for the floor and 3x6 inch subway tiles for the shower. Floor tiles come 20 per box at $18, subway tiles come 50 per box at $22. He uses 15% waste for the shower due to cuts around the niche and bench:

• Floor: 66 sq ft adjusted, 263 tiles, 14 boxes = $252
• Shower: 92 sq ft adjusted, 714 tiles, 15 boxes = $330
• Total tile cost: $582
• Total grout: 79 lbs, Total thinset: 3 bags

James runs each area through the calculator separately since the tile sizes and waste factors differ. The combined material cost for tile, grout, and thinset is approximately $660.

Example 3: Angela's Entryway Diagonal Layout

Angela wants a diagonal tile layout in her 100 square foot entryway using 18x18 inch porcelain tiles. The diagonal layout increases waste to 15%. Tiles come 5 per box at $55 per box with 1/8 inch gaps:

• Tile area: ((18 + 0.125) x (18 + 0.125)) / 144 = 2.284 sq ft per tile
• Adjusted area: 100 x 1.15 = 115 sq ft
• Tiles needed: 115 / 2.284 = 51 tiles
• Boxes: 51 / 5 = 11 boxes
• Tile cost: 11 x $55 = $605

The diagonal layout uses about 5% more tiles than a straight layout would. Angela appreciates the visual impact the diagonal pattern creates, making her entryway feel larger and more dynamic than a standard grid layout.

Tile Reference Table

Table includes 10% waste factor. Tiles per sq ft are approximate. Grout and thinset estimates based on standard application rates.

Tips and Complete Guide

Preparing the Surface for Tile Installation

Proper surface preparation is the foundation of a long-lasting tile installation. The substrate must be flat, clean, structurally sound, and dry. For concrete floors, fill any cracks or low spots with a self-leveling compound and ensure the surface is free of paint, sealers, or curing compounds that prevent thinset adhesion. For wood subfloors, install cement backer board (CBU) over the plywood using thinset and backer board screws spaced every 8 inches. The total floor assembly including subfloor and CBU should be at least 1.25 inches thick to prevent flexing. For walls, use moisture-resistant backer board in wet areas like showers and tub surrounds. Allow any leveling compound or fresh concrete to cure fully before tiling.

Selecting the Right Grout and Thinset

Use unsanded grout for gaps 1/8 inch or narrower and sanded grout for gaps wider than 1/8 inch. Epoxy grout offers superior stain and water resistance for kitchens and wet areas but is more difficult to work with and costs 3 to 5 times more than cementitious grout. For thinset, use a modified (polymer-enhanced) thinset for porcelain tiles and any tile installed on backer board, as the polymers improve adhesion and flexibility. Use unmodified thinset when installing tile over a waterproof membrane, as modified thinset needs air exposure to cure properly. White thinset is recommended for light-colored natural stone and glass tiles to prevent color bleed-through.

Layout Planning for Professional Results

Before applying any thinset, dry-lay tiles across the room to plan your layout. Start by finding the center of the room and snapping chalk lines to create a grid. Place tiles along both axes and adjust the starting point so that cut tiles at opposite walls are equal in width and no narrower than half a tile. Thin slivers of tile along walls look unprofessional and are prone to cracking. For diagonal layouts, snap 45-degree chalk lines from the center point. For brick-pattern layouts, offset each row by exactly half a tile length for a consistent look. Planning the layout before installation prevents costly mistakes and ensures a professional appearance.

Common Mistakes to Avoid

• Underestimating tile quantity: Ordering the exact number of tiles without a waste factor leaves you short after cuts and breakage. Always add at least 10% and keep spare tiles for future repairs. Tiles from different production runs may not match in color.
• Skipping the dry layout: Jumping straight into thinset application without dry-laying first often results in thin, awkward cuts along walls and misaligned patterns. Spend 30 minutes on a dry layout to save hours of frustration.
• Using the wrong trowel size: Too small a trowel means insufficient thinset coverage, causing hollow spots and loose tiles. Too large a trowel wastes material and creates uneven surfaces. Match trowel notch size to tile size for optimal coverage.
• Grouting too soon: Thinset needs 24 hours to cure before grouting. Walking on or grouting tiles before the thinset has set can shift tiles out of alignment and compromise the bond.
• Ignoring expansion joints: Tile installations need expansion joints at perimeters, transitions, and every 20 to 25 feet of continuous tile. Fill these with flexible caulk, not grout, to accommodate seasonal expansion and contraction.

Frequently Asked Questions