How many milliliters in a gallon? Calculatorology
2020-05-22· How many milliliters in a gallon? The volume units' conversion factor of gallons to milliliters is 3785.41178. 1 Gallon (Fluid, US) = 3785.41178 Milliliters. 1 Gallon (UK) = 4547 Milliliters. This means that there are 3785.41178 milliliters in one US fluid gallon and 4547 milliliters in one imperial gallon.