Re: How do you convert gallons into kilos??

The first thing to do is to determine, or look up, the density of the liquid (I'm assuming you're working with a liquid since you have "gallons", which is a liquid measure!). Let's say, for instance, that you are working with water. Its density is 1.0 grams per cubic centimeter (at 4^o C), or 1000 kilograms per cubic meter, and doesn't vary very much for typical ambient temperatures. See this table at Simetric. "Kilograms" is what you asked for so I'll use 1000 kilograms per cubic meter for the density.

The next thing to do is to convert gallons to cubic meters. You can find the conversion factor in many places, such as at convert-me.com, which gives the conversion as 0.0037854 cubic meters per gallon.

So, if you have one gallon of water you have 0.0037854 cubic meters, and if you multiply that times 1000 kilograms per cubic meter (water's density) you get 3.7854 kilograms. (There are 2.2046 pounds per kilogram [This is mixing weight and mass, but that's another story!], so the one gallon of water is 8.35 pounds.)

If the liquid is not water you will have to find its density, and multiply that times the volume in compatible units.

John Link, MadSci Physicist