This calculator estimates the exact number of tiles, tile boxes, and grout coverage you need to floor a room, tile a bathroom wall, or install a kitchen backsplash. It factors in tile dimensions, room square footage, grout joint spacing, and cutting waste so you avoid mid-project shortages.
- 1
Surface Dimensions: Enter the length and width of the floor or wall in feet, meters, or inches.
- 2
Tile Size: Enter the length and width of each individual tile in inches or centimeters (for example, 12×24 inches or 30×60 cm).
- 3
Grout Joint Width: Specify your grout spacing (standard 1/8 inch, narrow 1/16 inch, or wide 1/4 inch).
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Waste Factor: Keep the standard 10% for straight grid layouts, or increase to 15% for herringbone or diagonal patterns.
- 5
Box Pack Size: Enter how many tiles come in one retail box to calculate the exact number of full boxes to buy.
- The Concept: Measuring square footage alone is not enough because cutting edge tiles creates scrap you cannot reuse. Grout lines take up physical surface area, while corner cuts around doors and pipes waste material. Adding a 10% buffer guarantees you finish the job with matching dye lots.
- The Formula:
- Total Room Area = Length × Width
- Tile Area With Grout = (Tile Length + Grout Width) × (Tile Width + Grout Width)
- Net Tiles = Total Room Area / Tile Area With Grout
- Total Tiles to Order = Net Tiles × (1 + Waste Percentage / 100)
- Total Boxes = Round Up (Total Tiles to Order / Tiles Per Box)
Suppose you want to tile a 10 ft by 12 ft bathroom floor using 12×12 inch tiles with a 10% waste buffer. Each retail box holds 10 tiles.
- 1
Total Room Area = 10 ft × 12 ft = 120 sq ft.
- 2
Net tile count = 120 tiles (since each 12×12 inch tile equals 1 sq ft).
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Add 10% waste margin: 120 × 1.10 = 132 tiles needed.
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Calculate boxes: 132 / 10 = 13.2 boxes, rounded up to 14 full boxes.
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Buying 14 boxes gives you 140 tiles, leaving you 8 spare tiles for future repairs.
