To determine the square feet of backsplash that you will need for your project, you will need to use a tape measure and find the dimensions (height and width) of the area you plan to cover. Most areas are not a single height or width, but can be broken up into separate areas. In the example below we have three areas to be covered by new backsplash. The instructions shown below - Backsplash Square Feet Planning - can also be downloaded (pdf) and printed.
For all trims, just measure the length of the panel's edge or corner to be covered and purchase enough to cover.