You are benefitting from the true Imperial pint where there is 4546 mL per gallon. And of course 4 quarts to the gallon and two pints to the quart. Otherwise

You are benefitting from the true Imperial pint where there is 4546 mL per gallon. And of course 4 quarts to the gallon and two pints to the quart. Otherwise like in the US in what is commonly known as the English system there is only 3785 mL to the gallon.