Formula to convert 51.1 liters to gallons is to multiply 51.1 by 0.264172 (this is the value for 1 liter to gallon).
Convert 51.1 Liters to Gallons results
51.1 x 0.264172052 = 13.49919187764
51.1 l = 13.5 gal
To conclude the answer for 51.1 liters is thirteen point five gallons