Gallons to Pounds Converter
Gallons measure volume and pounds measure weight, so the liquid matters: a US gallon of water weighs about 8.34 lb, milk 8.6 lb, and gasoline only about 6.1 lb.
Example: with Volume 1 · Volume unit US gallons · Liquid Water (8.345 lb/gal) · Custom pounds per gallon 8.345 → Weight: 8.35 lb.
Computed by the calculator below using its default values. Change any input to see your own numbers.
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Check it outHow many pounds is a gallon?
Multiply gallons by the liquid’s pounds-per-gallon. Water is 8.345 lb/gal at its densest (about 39°F); at ordinary room temperature the working figure is 8.33–8.34 lb. So a 5-gallon jug of water weighs 5 × 8.345 ≈ 41.7 lb before you count the container — one reason full water-cooler bottles feel so brutal. Milk runs slightly heavier at about 8.6 lb/gal, honey a hefty 11.85 lb/gal, while gasoline (≈6.1 lb) and diesel (≈7.1 lb) float on water.
For metric volumes, use the liter option: 10 liters of water is 10 kg, which converts to 22.05 lb. The calculator turns liters into gallons (3.7854 L each) first, then applies the same density. If you only have a density in g/mL, multiply it by 8.345 to get lb/gal — e.g. bleach at 1.1 g/mL is about 9.2 lb/gal.
How it’s calculated
Weight (lb) = volume (US gal) × density (lb/gal), with liters converted first via 1 US gal = 3.785411784 L (NIST). Water uses 8.345 lb/gal, its maximum-density value near 39°F (USGS cites 8.34 lb at room temperature); whole milk 8.6 lb/gal (dairy-industry standard), gasoline ≈6.1 and diesel ≈7.1 lb/gal (typical fuel densities of 0.73 and 0.85 g/mL), honey 11.85 lb/gal (1.42 g/mL). Kilograms use 1 lb = 0.45359237 kg exactly.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Common mistakes
- Using water’s 8.34 lb/gal for every liquid — gasoline is about 27% lighter and honey about 42% heavier.
- Forgetting the container: a filled 5-gallon bucket adds the bucket’s own 1–2 lb on top of roughly 42 lb of water.
- Mixing up US and imperial gallons — the imperial gallon is 4.546 L, so a gallon of water in the UK weighs about 10 lb.
Frequently asked questions
How many pounds is a gallon of water?
About 8.34 lb at room temperature (8.345 lb at its densest, near 39°F). Hot water weighs slightly less — just under 8 lb per gallon near boiling.
How much does 5 gallons of water weigh?
5 × 8.345 ≈ 41.7 lb, plus the jug. A typical filled 5-gallon water-cooler bottle totals roughly 43 lb.
How many pounds is a gallon of milk?
About 8.6 lb, the long-standing dairy conversion. Milk is roughly 3% denser than water because of its dissolved solids.
How many pounds is 10 liters?
For water, 10 L weighs 10 kg = 22.05 lb. For other liquids, multiply 22.05 by the density in g/mL — 10 L of gasoline is only about 16 lb.
Does a gallon of gas really weigh less than water?
Yes — gasoline is about 6.1 lb per gallon (0.7–0.75 g/mL), which is why fuel floats on water and why a full 12-gallon tank adds only about 73 lb.