Multiply the number of kilometers cubed by 1 billion to convert to meters cubed. For example, if you have 20 km^3, multiply 20 by 1 billion to get 20 billion m^3.
Divide the number of kilometers cubed by 0.000000001 to convert to meters cubed. In this example, check your answer by dividing 20 by 0.000000001 to get 20 billion m^3.
Verify your answer with an online kilometers cubed-to-meters cubed calculator, such as provided in the Resources. Enter the number of kilometers cubed and the site will display the number of meters cubed.