Tile Calculator

Calculate how many tiles you need for floors, walls, or backsplashes. Supports different tile sizes and includes waste allowance.

Area Dimensions

Length (feet)

Width (feet)

Tile Sizing

Tile Length (inches)

Tile Width (inches)

Grout Joint (inches)

Waste Allowance (%)

Tiles Per Box (optional)

Tile Estimation Results

SPEC_VERIFIED

Total Tiles Needed (with waste)

130tiles

Boxes Needed

13boxes

Detailed Material Breakdown

Exact Tiles (no waste): 118tiles
Surface Area: 120 sq ft (11.15 m²)

Calculation Formula & Assumptions

The tile calculator computes the total surface area to be tiled and divides it by the effective coverage of an individual tile (including the grout joint width), then adds a waste contingency.

Total Tiles = ⌈(Room Length × Room Width) ÷ ((Tile Length + Grout) × (Tile Width + Grout)) × (1 + Waste %)⌉

Step-by-step breakdown:

Convert room/wall length and width to feet: Area = Length × Width
Convert tile dimensions to feet and add grout joint width: Effective Tile Area = (Tile Length + Grout Gap) × (Tile Width + Grout Gap)
Divide total area by tile coverage to find raw tiles needed: Tiles = Area ÷ Effective Tile Area
Apply waste factor: Tiles with Waste = Ceiling(Tiles × (1 + Waste % ÷ 100))
If box packaging is provided, divide tiles with waste by tiles per box and round up to the nearest whole box.

Note: For diagonal or herringbone patterns, increase the waste factor from 10% to 15%–20% to account for perimeter triangle cuts.

Worked Calculation Example

Master Bathroom Floor (10×12 ft) with 12×24" Tiles

Tiling a rectangular master bathroom measuring 10 feet wide by 12 feet long using 12×24 inch porcelain tiles with a 1/8" grout joint and a 10% waste allowance.

Room Dimensions:10 ft × 12 ft (120 sq ft)

Tile Dimensions:12 inches × 24 inches (1.0 ft × 2.0 ft)

Grout Joint:0.125 inches (0.0104 ft)

Waste Allowance:10%

Box Packaging:8 tiles per box (16 sq ft)

Calculation Steps:

Room Area = 10 ft × 12 ft = 120.00 sq ft (11.15 sq meters)
Tile Area without grout = 1 ft × 2 ft = 2.00 sq ft per tile
Raw tiles needed = 120 ÷ 2.0 = 60 tiles
With 10% waste factor: 60 × 1.10 = 66 tiles
Boxes needed = 66 ÷ 8 tiles/box = 8.25 => 9 boxes (144 sq ft total)

Purchase 9 boxes of tile (72 tiles total) to ensure ample material for cuts and contingency.

How to Use This Calculator

Select your preferred measurement units (Feet or Meters for room area; Inches or Centimeters for tile size).
Enter the length and width of the floor, wall, or backsplash area to be tiled.
Enter the dimensions of your individual tile (e.g., 12×12, 12×24, or 3×6 inches).
Enter the planned grout joint width (typical standard joints are 1/16", 1/8", or 3/16").
Choose a waste percentage (10% for straight grid; 15% for diagonal; 20% for herringbone or irregular rooms).
Optional: Enter tiles per box from the manufacturer carton to calculate total boxes needed.

Pro Tips:

Always purchase all tile in a single order to ensure consistent manufacturing dye-lot and caliber sizing.
Store at least one unopened box of leftover tiles for future plumbing or floor repairs.

Common Estimation Mistakes to Avoid

Neglecting the waste allowance for perimeter cuts, resulting in running short on the last row.
Mixing different dye-lots by buying extra tile weeks later when initial stock runs out.
Using a 10% waste allowance for a 45-degree diagonal layout where 15% to 20% is required.
Not measuring alcoves, under-vanity spaces, or closets within the room footprint.

Frequently Asked Questions

Order 10% extra for standard square or rectangular rooms with straight grid patterns. For diagonal layouts, order 15% extra. For complex patterns like herringbone or rooms with many angles, order 15% to 20% extra.

Tile is manufactured in kiln batches called dye-lots. Natural variations in minerals and firing temperatures produce slight color and size variations between batches. Ordering everything at once prevents mismatched shades.

Calculate total backsplash length times height. Small electrical outlet cutouts should NOT be deducted; keeping them in your total provides a natural buffer for the detailed cuts required around boxes.