Gallons measure volume and kilograms measure weight — converting between them depends on the liquid’s density, not a fixed ratio.
How it works
Gallons are converted to liters using the exact US gallon definition, then multiplied by the liquid’s density to get kilograms. The default density is water’s.
What this does not include
This does not include a built-in density lookup for specific liquids — check a reliable source for the exact density of whatever liquid you’re measuring if it isn’t water.
How to use this calculator
- Enter the gallons and the liquid’s density (defaults to water).
Frequently asked questions
How many kilograms is a gallon of water?
About 3.785 kilograms, the default result of this calculator.
Is this the reverse of the site’s kg-to-gallons calculator?
Yes — same underlying density-based method, just starting from the opposite unit for the “gallons to kg” search direction.
Does milk weigh the same as water per gallon?
Close, but milk is slightly denser than water, so a gallon of milk weighs a bit more than a gallon of water.
