MINIMUM + MAXIMUMS
Average kitchen island size is 80 by 40 inches.
Standard height of an island is 36 inches, but if it is used for seating, the standard size is 42 inches tall.
As for floor space around the island, 36 to 42 inches around all sides is the suggested clearance zone, and 48 if multiple people will be using different areas of the kitchen at the same time.