This backsplash estimator calculator is designed to give an approximate quantity for materials needed for a backsplash installation. While we assume regular dimensions, you can estimate irregular dimensions fairly well. Measure the length of the backsplash area (at the longest point if irregular) and the height of the backsplash area (at the widest point if irregular). Enter the values. Click on Calculate for the values returned. We round up on most measurements. These are estimates only, though from history, very close. Actual pieces, sizes and quantities may vary due to many circumstances, including variable backsplash areas, irregular shaped rooms or areas, outlets, switches, and similar potential problems. Regular areas are very close. Please use this as a good starting point. A good general rule of thumb if you are special ordering is order 10-15% more than you need in case you make a mistake. Remember, always measure twice and cut once.