How to Calculate the Waist in Ceramic Tile

Every tile job involves a certain amount of waste tile, or tile factored in to the total purchased that is above and beyond the amount needed to cover an area.

Border and specialty tiles should include one or two extra pieces for waste.Border and specialty tiles should include one or two extra pieces for waste.
Waste tile is needed in case of breakage, or if multiple tiles are being cut, such as with diagonal or multiple piece tile patterns. Even the most simple ceramic tile installations will require at least a small amount of waste. The more complicated the pattern, the more waste that is required.

Calculate the amount of ceramic tile needed for the job by measuring the space in inches, multiplying the length and width together and dividing this number by 144 -- one square foot. Round up to the nearest whole foot.

For straight tile patterns, or straight rows of tile, add 5 percent, rounded to the nearest whole number, to the total amount required for the job as figured in Step 1. A room that measures 92 inches by 111 inches will need 71 square feet of tile plus an extra 4 square feet of waste for a total of 75 square feet of tile.

For diagonal patterns or multiple piece patterns that require different sizes of tile or special laying, add 15 percent for waste. So the room that requires 71 square feet of tile will need an additional 11 square feet of waste -- 82 square feet of tile.

For decorative cut-in tiles, add one additional piece for small jobs of less than 10 decoratives per installation and two additional pieces for larger jobs of more than 10 decoratives.

Things You Will Need

  • Measuring tape
  • Calculator


  • Most ceramic tiles are sold in full boxes. Round up to the nearest full box, not down. Save any leftover tiles for repairs to the job in the future.

About the Author

Sarabeth Asaff has worked in and has written about the home improvement industry since 1995. She has written numerous articles on art, interior design and home improvements, specializing in kitchen and bathroom design. A member in good standing with the National Kitchen and Bath Association, Asaff has working knowledge of all areas of home design.