Formula to convert 13.5 liters to gallons is to multiply 13.5 by 0.264172 (this is the value for 1 liter to gallon).
Convert 13.5 Liters to Gallons results
13.5 x 0.264172052 = 3.5663227074
13.5 l = 3.57 gal
To conclude the answer for 13.5 liters is three point fifty seven gallons