Most of our premium fire glass comes in standard (10) pound increments - (10) pounds of fire glass amounts to a volume that is slightly less than 1 gallon. Think about a gallon of milk, and imagine that (10) pounds of fire glass will not quite fill that gallon jug. So how much do you need? Use our fire pit calculator and enter in the dimensions (in inches) you wish to fill. Usually, we recommend covering your burner until just covered, which can take anywhere from 1.5" to 4". Commonly, people find they end up needing more fire glass than they originally anticipated; for example - a standard 18" burner ring with a 24" diameter opening needs roughly (70) pounds, while a 24" burner ring with a 30" diameter opening needs roughly (110) pounds.