How Many Pounds (lbs) Are in a Gallon?
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Conversion Formulas
Feel free to convert pounds (lbs) to gallons and gallons to pounds (lbs) using our conversion chart, conversion calculator, and learn the relationship between these two units.
Conversion of pounds (lbs) to gallons and gallons to pounds (lbs) is an easy one, but one must be aware that the pound (lbs) is a unit of mass, while the gallon is a unit of volume, and some assumptions must be made.
One pound (lb) is a unit of mass and it is defined as having exactly 0.45359237 kg. Over time various pounds were in use, but now the pound is standardized using SI unit for mass  kilogram.
Gallon is unit of volume and it is defined as:
1 US Liquid Gallon = 128 US Fluid Ounces (fl oz) = 3.78541 liters = 3.78541 kg (of water) = 8.3454 lbs (of water)
1 Imp Liquid Gallon = 160 Imp Fluid Ounces = 4.54609 liters = 4.54609 kg (of water) = 10.0224 lbs (of water)
So, for short:
1 US Liquid Gallon = 8.3454 lbs (of water)
1 Imp Liquid Gallon = 10.0224 lbs (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, by multiplying the weight of water for the given volume with the density of the liquid in question (hint: the density of water is 1 kg/liter).
For example, if we have 1 gallon (US/Imp) of gasoline (0.75 kg/liter) and 1 gallon of diesel (0.875 kg/liter), that would be:
1 US Liquid Gallon_{(gas)} = 3.78541 liters → M_{(gas)} = 3.78541 liters * 0.75 kg/liter = 2.839 kg = 6.259 pounds
1 Imp Liquid Gallon_{(gas)} = 4.54609 liters → M_{(gas)} = 4.54609 liters * 0.75 kg/liter = 3.409 kg = 7.515 pounds
1 US Liquid Gallon_{(diesel)} = 3.78541 liters → M_{(diesel)} = 3.78541 liters * 0.875 kg/liter = 3.312 kg = 7.302 pounds
1 Imp Liquid Gallon_{(diesel)} = 4.54609 liters → M_{(diesel)} = 4.54609 liters * 0.875 kg/liter = 3.978 kg = 8.77 pounds
Conversion Examples
How many lbs is 2 gallons of water?
If You have 2 gallons (US/Imp) of water that would be:
M(water) = 3.78541 * V(US gallon) = 3.78541 * 2 = 7.57082 liters = 7.57082 kg = 16.6908 lbs
M(water) = 4.54609 * V(Imp gallon) = 4.54609 * 2 = 9.09218 liters = 9.09218 kg = 20.0448 lbs
How many lbs is 5 gallons of water?
If You have 2 gallons (US/Imp) of water that would be:
M(water) = 3.78541 * V(US gallon) = 3.78541 * 5 = 18.927 liters = 18.927 kg = 41.727 lbs
M(water) = 4.54609 * V(Imp gallon) = 4.54609 * 5 = 22.730 liters = 22.730 kg = 50,112 lbs
Pounds (lbs) to Gallons and Gallons to Pounds (lbs) Conversion Calculator
In order to convert pounds to gallons and gallons to pounds, 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):
Pounds (lbs) to US Fluid Gallons 
Pounds (lbs): US Fluid Gallons: 
US Fluid Gallons to Pounds (lbs) 
US Fluid Gallons: Pounds (lbs): 
Pounds (lbs) to Imperial Gallons 
Pounds (lbs): Imperial Gallons: 
Imperial Gallons to Pounds (lbs) 
Imperial Gallons: Pounds (lbs): 
Pounds to Gallons and Gallons to Pounds Conversion Charts
Here are some pounds to gallons and gallons to pounds 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):
Pounds  US Gallons  Imperial Gallons 
1  0.1198  0.0997 
2  0.2396  0.1995 
3  0.3594  0.2993 
5  0.5991  0.4988 
8  0.9586  0.7982 
10  1.198  0.9977 
20  2.396  1.9955 
30  3.594  2.9932 
50  5.991  4.9888 
100  11.98  9.9776 

