Convert between gallons and pounds based on substance density. Essential for cooking, fuel calculations, and liquid weight estimation.
Last updated: March 2026 | By Patchworkr Team
Converting between volume (gallons) and weight (pounds) requires knowing the density of the substance. Different liquids have different densities, so a gallon of honey weighs much more than a gallon of gasoline.
For water at standard conditions, 1 US gallon weighs approximately 8.345 pounds. This is a commonly used reference point. The exact weight varies slightly with temperature, as water density changes with temperature.
This conversion is essential in many industries: fuel delivery, cooking and baking, chemical processing, and agriculture. Always use the specific density of your substance for accurate conversions.
One US gallon of water weighs approximately 8.345 pounds at room temperature (about 62°F/17°C). This can vary slightly with temperature as water density changes.
Weight per gallon depends on density, which is determined by molecular structure and packing. Honey is denser than water, so it weighs more per gallon. Gasoline is less dense, so it weighs less.
You need to know the substance's specific gravity (density relative to water). Multiply 8.345 lbs/gal by the specific gravity. For example, a substance with SG 1.5 weighs 8.345 × 1.5 = 12.52 lbs/gal.
Yes! Liquids expand when heated and contract when cooled, changing their density. Water at 40°F weighs about 8.35 lbs/gal, while at 100°F it weighs about 8.29 lbs/gal.
This calculator uses US gallons (3.785 liters). If you need Imperial gallons (4.546 liters), multiply the result by 1.2 to approximate the conversion.
Fuel weight is crucial in aviation, trucking, and marine applications for load calculations, fuel economy, and safety. A gallon of jet fuel weighs about 6.8 lbs, significantly affecting aircraft weight.
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