* Conversions:

* 1 gallon = 3.785 liters

* 1 liter = 1000 ml

* Calculations:

* 1 gallon = 3.785 liters * 1000 ml/liter = 3785 ml

* 3785 ml / 750 ml/bottle = 5.04 bottles

Therefore, there are approximately 5.04 bottles of 750 ml in 1 gallon.