How much smaller is 0.5 liters smaller than 650 ml?

To compare the two volumes, we need to convert both measurements to the same unit. Since 1 liter is equal to 1000 ml, 0.5 liters is equal to 500 ml. To find the difference, we subtract 500 ml from 650 ml, which equals 150 ml. Therefore, 0.5 liters is 150 ml smaller than 650 ml.