Tile Calculator
By Emiliano · Last updated 2026-09-27
Accurately estimate tiles, boxes, thinset, and grout for your flooring or wall project.
How this calculator works
This calculator determines the total area of your space by multiplying the length and width. It then calculates the individual surface area of one tile and divides the total room area by the tile area to find the base quantity. Finally, it applies your selected waste percentage and estimates standard thinset and grout requirements based on typical coverage rates.
Authoritative Source: TCNA Handbook for Ceramic, Glass, and Stone Tile Installation.
How to Calculate Tile Needs
To calculate how many tiles you need for a floor or wall, you must first determine the total area of the surface. For a standard rectangular room, multiply the length by the width. For example, a room measuring 12 feet by 10 feet (approximately 3.6 meters by 3.0 meters) has an area of 120 square feet (11.1 square meters).
Next, calculate the area of a single tile. If you are using standard 12x12 inch (30x30 cm) tiles, each tile covers exactly 1 square foot (0.09 square meters). Divide the total room area by the single tile area to find the base number of tiles required. In this example, 120 square feet divided by 1 square foot equals 120 tiles.
Always add a waste factor to account for cuts, breaks, and mistakes. A standard straight layout typically requires a 10% waste factor, whereas diagonal or herringbone patterns require 15% to 20% extra material. Multiplying your base tile count by 1.10 gives you the final target number of tiles to purchase.
What Affects Tile and Material Quantities
Several variables impact the actual volume of tile, mortar, and grout you will need to order. The layout pattern is the most significant factor; complex designs like herringbone or chevron require intricate diagonal cuts along the perimeter, which increases waste compared to a standard grid layout.
The size and type of tile also dictate your thinset mortar requirements. Large format tiles—defined as any tile with one side longer than 15 inches (38 cm)—require a thicker mortar bed and a larger trowel, such as a 1/2 inch (12 mm) square-notched trowel. This increases thinset consumption compared to smaller mosaic tiles that only require a 1/4 inch (6 mm) trowel.
Substrate flatness is another critical variable. If your concrete slab or backer board has dips or high spots, you will use significantly more thinset to level the surface during installation. Grout quantities are determined by the depth and width of the grout joints, which typically range from 1/16 inch (1.5 mm) for rectified tiles to 1/4 inch (6 mm) or wider for rustic pavers.
Frequently Asked Questions
How much extra tile should I buy for waste?
For standard square or rectangular installations, we recommend adding 10% to your total area. If you are installing tiles diagonally, in a herringbone pattern, or working in a room with many corners and obstacles, increase the waste factor to 15% or 20% to ensure you do not run out of material mid-project.
How many bags of thinset mortar do I need?
On average, a standard 50-pound (22.7 kg) bag of dry thinset mortar covers approximately 50 to 95 square feet (4.6 to 8.8 square meters) when using a standard 1/4 inch (6 mm) trowel. Larger trowels used for heavy tiles will reduce this coverage to about 40 to 50 square feet (3.7 to 4.6 square meters) per bag.
How do I calculate tiles for an irregular room?
For L-shaped or highly irregular rooms, break the floor plan down into smaller, manageable rectangles. Calculate the area of each individual rectangle (Length x Width), add those areas together to get the total square footage (or square meters), and then proceed with the standard tile size calculations.