Tile Calculator

Use our free tile calculator to determine how many tiles you need for a floor or wall installation. Built for homeowners, tilers, and contractors, it accounts for room dimensions, tile size, grout joint width, and a waste factor for cuts and breakage. Enter your floor dimensions and tile specs to get an instant tile count.

Grout width might look like a minor detail, but on a large floor it changes the tile count by several tiles once you multiply it across every row and column. That's why this calculator adds the grout joint to each tile dimension rather than just dividing the floor area by the tile's raw face size, which would overstate how many tiles fit and leave you short on order day.

How to use this calculator.

1. Enter floor dimensions. Input the floor length and width in feet. For irregular rooms, break the area into rectangles and sum them first.
2. Enter tile size. Input tile length and width in inches, as printed on the box.
3. Set the grout width. The default is 1/8 in (0.125); adjust for wider joints on standard ceramic or natural stone.
4. Set the waste factor. Default 10%; increase to 15–20% for diagonal or herringbone layouts.
5. Review your results. Floor area and tiles needed calculate instantly when you click Calculate.

How do you calculate A tile calculator helps you determine exactly how many tiles you need for a flooring project. It accounts for room dimensions, tile size, grout joint width, and a waste factor for cuts and breakage.?

Because each tile actually occupies a footprint of tile-plus-grout, the calculator adds the grout width to each tile dimension before dividing it into the floor area.

Floor Area (sq ft) = Floor Length × Floor Width

Tiles Needed = (Floor Area × 144) ÷ [(Tile Length + Grout Width) × (Tile Width + Grout Width)] × (1 + Waste %)

Where:

• Floor Area × 144: Converts the floor area from square feet to square inches, matching the tile dimensions.
• Tile Length / Tile Width: The tile's dimensions, in inches.
• Grout Width: The joint width between tiles, in inches, added to each tile dimension to get its true installed footprint.
• Waste %: Extra tiles for cuts, pattern matching, and breakage, typically 10–20%.

Example calculation.

Let's estimate tile for a 12 ft by 10 ft kitchen floor using 12-inch square tiles, 1/8 in (0.125 in) grout joints, and a 10% waste factor. Tiles come 15 per box.

1. Floor area: 12 ft × 10 ft = 120 sq ft
2. Convert to sq inches: 120 sq ft × 144 = 17,280 sq in
3. Tile footprint with grout: (12 + 0.125) × (12 + 0.125) = 12.125 × 12.125 = 147.02 sq in
4. Tiles needed before waste: 17,280 ÷ 147.02 = 117.5 tiles
5. Apply 10% waste: 117.5 × 1.10 = 129.3 → round up to 130 tiles
6. Boxes needed: 130 ÷ 15 per box = 8.7 → round up to 9 boxes

Result: You need approximately130 tiles: purchase 9 boxes(135 tiles) to complete this floor.

Tips from the field.

• Buy extra for future repairs. Keep at least one full box of tile after installation. If a tile cracks years later, you will have a matching replacement from the same dye lot.
• Pattern layout matters. Herringbone and diagonal layouts can generate 15–20% waste. Straight lay patterns are the most efficient, typically 5–10%.
• Large-format tiles need flat floors. Tiles larger than 15 in on any side require a very flat substrate. Floor unevenness can cause lippage (edges sticking up) and increase breakage.
• Check dye lot numbers. Tiles from different production runs can have visible color variation. Verify all boxes share the same dye lot before accepting delivery.
• Wider grout hides sizing variance. Handmade or natural stone tiles are rarely perfectly uniform; a wider grout joint (3/8–1/2 in) makes small size differences less noticeable.

Disclaimer: Calculations are estimates. Actual tile requirements vary with room shape, layout pattern, grout joint width, and substrate conditions. Always have a professional measure for large or complex installations before ordering materials.