Formula to convert 4.2 gallons to liters is to multiply 4.2 by 3.75841178 (this is the value for 1 gallon to liter).
Convert 4.2 Gallons to Liters results
4.2 x 3.78541178 = 15.898729476
4.2 gal = 15.9 l
It’s simple, the answer for 4.2 gallons is fifteen point nine zero liters