Fuel Tank Capacity Calculator

Unlike water (density = 1.00 kg/L), hydrocarbon fuels are significantly lighter than water. Gasoline has a baseline density of ~0.75 kg/L (6.26 lbs/US gal), automotive diesel is ~0.832 kg/L (6.94 lbs/US gal), and E85 ethanol is ~0.789 kg/L at standard reference temperature (15°C / 59°F). Knowing fuel mass is essential for payload calculations in aviation, motorsport, and commercial logistics.

Formula: Mass (kg) = Volume (L) × Fuel Density (kg/L); Mass (lbs) = Volume (gal) × Density (lbs/gal)

• Gasoline Density: 0.750 kg/L (0.71 - 0.77 kg/L range depending on winter/summer blend)
• Diesel #2 Density: 0.832 kg/L (0.82 - 0.86 kg/L range)
• Ethanol (E85) Density: 0.789 kg/L at standard 15°C

• 60-Liter Gasoline Tank Mass: 60 L × 0.750 kg/L = 45.0 kg (99.2 lbs of onboard fuel weight) = 45.0 kg fuel weight added to vehicle curb weight
• 100-Liter Heavy Diesel Tank Mass: 100 L × 0.832 kg/L = 83.2 kg (183.4 lbs) = 83.2 kg fuel payload

Liquid fuels expand as temperature rises according to their coefficient of volumetric thermal expansion (β ≈ 0.00095 to 0.0010 per °C for gasoline). In high summer heat (35°C vs 15°C baseline), 50 liters of fuel expands by roughly 1 liter. At high altitudes (e.g. 2,500m above sea level), barometric pressure reduces air density, altering the stoichiometric air-fuel ratio and evaporation rates.

Formula: V_adjusted = V_base × [1 + β × (T - 15°C)]; ρ_adjusted = ρ_base × [1 - altitude × 0.00001]