How Many Grams Are in a Gallon?
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Conversion Formulas
Convert grams to gallons and gallons to grams using our conversion chart, conversion calculator, and learn the relationship between these two units.
Conversion of grams to gallons and gallons to grams is an easy one, but one must be aware that the gram is a unit of mass, while the gallon is a unit of volume and some assumptions must be made.
Gram is a metric system unit of mass and it was first defined as a mass of 1 milliliter (1 cm^{3}) water at 0°C (later at 4°C)  modern definition of a gram and a kilogram is based on the fixed numerical value of the Planck constant h, but the actual difference is very small and can be ignored in everyday situations.
Thus, gallonsgrams conversion formulas are:
1 US Liquid Gallon = 128 US Fluid Ounces (fl oz) = 3.78541 liters = 3785.41 grams (of water)
1 Imp Liquid Gallon = 160 Imp Fluid Ounces = 4.54609 liters = 4546.09 grams (of water)
It must be emphasized that if You have a liquid that is less dense than the water (oil, gas/petrol, etc.) or denser than the water (salty water, for example) then in order to accurately convert the grams to gallons and gallons to grams, You also have to take the density of the liquid into account.
Conversion Examples
If You have 2 gallons (US/Imp) that would be:
V(g) = 3785.41 * V(US gallon) = 3785.41 * 2 = 7570.82 ml = 7570.82 grams (of water)
V(g) = 4546.09 * V(Imp gallon) = 4546.09 * 2 = 9092.18 ml = 9092.18 grams (of water)
Grams to Gallons and Gallons to Grams Conversion Calculator
In order to convert grams to gallons and gallons to grams, feel free to use this conversion calculator  write the value that You have and click 'Calculate' to convert it (again, values are very accurate for plain water, but for other liquids, You must also calculate in the liquids' densities):
Grams to US Gallons 
Grams: US Gallons: 
US Gallons to Grams 
US Gallons: Grams: 
Grams to Imperial Gallons 
Grams: Imperial Gallons: 
Imperial Gallons to Grams 
Imperial Gallons: Grams: 
Grams to Gallons and Gallons to Grams Conversion Charts
Here are some grams to gallons and gallons to grams quick conversion charts to aid You with units' conversions (again, values are very accurate for plain water, for other liquids, You must also calculate in the liquids' densities):
Grams  US Gallons  Imperial Gallons 
1  0.000264  0.000219 
10  0.00264  0.00219 
100  0.0264  0.0219 
453.6 (~1 lbs)  0.1198  0.0997 
1000  0.2641  0.2199 
2000  0.5283  0.4399 
3000  0.7925  0.6599 
4000  1.0566  0.8798 
5000  1.3208  1.0998 
10000  2.6417  2.1996 

