Formula to convert 51.5 liters to gallons is to multiply 51.5 by 0.264172 (this is the value for 1 liter to gallon).
Convert 51.5 Liters to Gallons results
51.5 x 0.264172052 = 13.6048606986
51.5 l = 13.6 gal
To conclude the answer for 51.5 liters is thirteen point six gallons