How much does a gallon of water weigh?

1 Gallon = 3.785 kgs

Gallon is a unit of measurement of liquid.

We know that 1 gallon = 3.785 liters

But we know that,

1 cubic meter = 1000 lit or 1000 kgs

=> 1 lit = 1 kg

Hence,  1 gallon = 3.785 lit = 3.785 kgs.