Example:
15 Pm/L = 6.819149e+16 meter per UK gallon
1 Pm/L = 4.546099e+15 meter per UK gallon | 1 meter per UK gallon = 2.199688e-16 Pm/L
Conversion Steps:
15 × (1e+15 / 0.219968799) = 6.819149e+16