Flat Top Griddle Grill for Gas, Electric or Charcoal GrillsThere are many grills and many different grill grate sizes. As these often change, make sure you order the correct size for your grill. The simplest way of making sure you get the right size is by measuring the grill grate that came with your grill. Then simply select the corresponding size from the drop down list. Many people also buy the size they like best and just lay it on top of the existing grill grates. Measure the overall length (long side)