How Much Does a Gallon of Diesel Weigh? (2026 Guide)
Quick Answer: One US gallon of diesel weighs approximately 7.1 pounds (3.22 kg). One UK Imperial gallon of diesel weighs about 8.5 pounds (3.86 kg). The exact weight varies slightly with temperature and fuel blend.
Diesel Weight: The Numbers
US Gallon
– ~7.1 lbs per gallon (3.22 kg)
– Density: ~0.85 kg/L
– Volume: 3.785 liters
UK Imperial Gallon
– ~8.5 lbs per gallon (3.86 kg)
– Volume: 4.546 liters (20% larger than a US gallon)
Why Diesel Weighs More Than Gasoline
A gallon of gasoline weighs about 6.1-6.3 lbs, roughly a full pound less than diesel. The reason: diesel molecules are longer hydrocarbon chains, packing more mass into the same volume. This higher energy density is exactly why diesel engines get better fuel economy – there’s literally more fuel energy in each gallon.
What Affects Diesel Weight?
Temperature: Diesel expands when warm and contracts when cold. The standard reference is 60°F (15.6°C). Cold diesel is slightly denser and heavier per gallon; hot diesel is lighter.
Fuel blend:
– Standard #2 diesel: ~7.1 lbs/gal
– #1 diesel (winter blend): slightly lighter, ~7.0 lbs/gal
– Biodiesel (B100): heavier, ~7.3-7.5 lbs/gal
– B20 blend (20% biodiesel): ~7.15 lbs/gal
Additives: Anti-gel additives and cetane improvers change weight negligibly.
Practical Applications
Trucking and Payload
A typical semi-truck carries 120-150 gallons of diesel:
– 120 gallons × 7.1 lbs = 852 lbs of fuel
– 150 gallons × 7.1 lbs = 1,065 lbs of fuel
That’s over half a ton just in fuel weight – a major factor in payload calculations.
Boat Fuel
Marine diesel tanks are often 50-200 gallons:
– 100 gallons = ~710 lbs (322 kg)
– This weight sits low in the hull, actually improving stability
Home Heating Oil
Heating oil is essentially the same as diesel:
– A 275-gallon home tank (filled to ~250 gallons) = ~1,775 lbs of fuel
– Delivery trucks account for this in their weight limits
Quick Reference Table
| Amount | Weight (US) |
|—|—|
| 1 gallon | 7.1 lbs / 3.22 kg |
| 5 gallons | 35.5 lbs / 16.1 kg |
| 10 gallons | 71 lbs / 32.2 kg |
| 55-gallon drum | ~390 lbs / 177 kg |
| 1 liter | 1.87 lbs / 0.85 kg |
Frequently Asked Questions
Does diesel weigh the same as water? No. Water weighs 8.34 lbs per US gallon – about 1.2 lbs more than diesel. Diesel floats on water, which is why water contamination in fuel tanks settles at the bottom.
Why does fuel weight matter? For aircraft, racing, trucking, and shipping, every pound affects fuel economy, payload capacity, and safety calculations.
Is red diesel the same weight? Yes – red diesel (off-road/agricultural) is chemically the same as regular diesel, just dyed for tax purposes. Same weight.
Conclusion
Remember 7.1 pounds per US gallon as your go-to figure for diesel weight. It’s heavier than gasoline but lighter than water – and that density difference is fundamental to how diesel engines achieve their legendary efficiency.