Gasoline vs. Kerosene: Which Is More Flammable?

Gasoline is more flammable than kerosene. At typical room temperatures, gasoline produces ignitable vapors far more readily because it has a very low flash point and high vapor pressure, while kerosene generally needs to be warmed before it emits enough vapor to ignite. This distinction drives how each fuel is classified, stored, and handled under safety standards.

What “more flammable” means

Flammability for liquids is primarily governed by how easily they form ignitable vapors. Key measures include flash point (the lowest temperature at which enough vapor forms to ignite), vapor pressure (how readily a liquid produces vapor), flammable limits in air (the concentration range in which vapors can ignite), and autoignition temperature (the temperature at which a substance ignites without a spark). In day-to-day safety terms, lower flash point and higher vapor pressure matter most because they determine whether dangerous vapor-air mixtures exist at ambient temperatures.

How gasoline and kerosene compare

Flash point and vapor pressure

Gasoline has a flash point around −43°C (−45°F) and a seasonally adjusted, relatively high vapor pressure (often 7–15 psi Reid Vapor Pressure), meaning it readily emits flammable vapors at normal temperatures. Kerosene’s flash point is much higher—typically 37–72°C (100–162°F)—and its vapor pressure is far lower, so at room temperature it produces far fewer vapors. Regulators reflect this gap: gasoline is classified as a flammable liquid (Class IB under OSHA), while kerosene is typically a combustible liquid (Class II or IIIA, depending on grade and flash point).

Autoignition temperature

Kerosene usually has a lower autoignition temperature (about 210–260°C / 410–500°F) than gasoline (roughly 280–470°C / 536–878°F). Despite this, gasoline remains the greater hazard in everyday conditions because it forms an ignitable vapor-air mixture far more easily; autoignition matters most in hot-surface scenarios rather than typical ambient environments.

Flammable limits in air

Gasoline vapors ignite across an approximate range of 1.4% to 7.6% by volume in air. Kerosene’s flammable range is narrower and typically cited around 0.7% to 5%. Because gasoline produces abundant vapor, it more readily reaches those concentrations near spills or open containers.

Standard hazard ratings

Under the NFPA 704 system, gasoline commonly carries a flammability rating of 3, while kerosene is typically 2—another indicator that gasoline presents a higher ignition risk under normal handling conditions.

Practical implications and safety

These properties translate directly into how each fuel should be handled in homes, workshops, and industrial sites. The goal is to minimize vapor formation, eliminate ignition sources, and use appropriate storage practices that match each fuel’s classification and volatility.

• Storage classification: Store gasoline in approved flammable-liquid containers; kerosene in approved combustible-liquid containers, away from heat.
• Ventilation: Ensure good airflow where gasoline is used or dispensed; vapors are heavier than air and can travel to ignition sources.
• Temperature control: Keep both fuels cool; elevated temperatures sharply increase gasoline vapor formation.
• Ignition sources: Eliminate sparks, open flames, and hot surfaces; use intrinsically safe equipment where appropriate.
• Spill response: Clean spills promptly; gasoline vapors can accumulate rapidly, while kerosene spills can wick and smolder if ignited.

Taken together, these practices recognize that gasoline poses a higher immediate ignition risk, while kerosene—though less volatile—still demands disciplined handling to prevent fires.

Bottom line

Gasoline is more flammable than kerosene because it vaporizes and reaches ignitable concentrations at ordinary temperatures. Kerosene’s higher flash point makes it less prone to ignition in everyday conditions, even though its autoignition temperature can be lower. Safety regulations, hazard ratings, and best practices all reflect this difference.

Summary

Gasoline is more flammable than kerosene. Its very low flash point and higher vapor pressure make gasoline far more likely to form ignitable vapor-air mixtures at room temperature. Kerosene, with a higher flash point and lower vapor pressure, is generally classified as combustible rather than flammable, indicating a lower—though still significant—fire risk under typical conditions.

What fuel is the most flammable?

Of all the dangerous chemical gases, chlorine trifluoride is known to be the most flammable. It is a colorless and extremely reactive gas that can burn through concrete and gravel.

Is gasoline still flammable if it dries up?

No, the liquid gasoline itself is no longer present once it has “dried” because it has evaporated into vapor, which is then flammable and can ignite if it’s mixed with air in the right concentration. The lingering hazard comes from these flammable vapors collecting in low spots or on absorbent materials, or from a thin film of liquid remaining, rather than a dry residue. 
What happens when gasoline “dries”

• Evaporation: Opens in new tabGasoline is designed to evaporate quickly because it is a mix of light hydrocarbons. When it “dries,” it has transformed into a gas (vapor) and dispersed into the air. 
• Vapor formation: Opens in new tabThe liquid gasoline turns into highly flammable vapors that can mix with air. 
• Flammability: Opens in new tabThe danger comes from these vapors, not a dry residue, as even a small spill can create a significant fire risk. 

Factors influencing drying and risk

• Temperature: Higher ambient temperatures cause gasoline to evaporate faster. 
• Air movement: Wind or air movement helps disperse the vapors, making them less concentrated and flammable. 
• Surface type: Gasoline evaporates quickly on non-porous surfaces, but it can remain on porous surfaces like soil, wood, or cloth. 
• Clothing: Clothes doused in gasoline remain a fire risk due to residual gasoline, so they should be discarded or washed but not put in a dryer. 

Why is kerosene used instead of gasoline?

Storing large amounts of kerosene is relatively safe compared to gasoline or propane, as it is less volatile and does not easily ignite. In conclusion, kerosene is an excellent choice for off-grid living and emergencies, providing a dependable and affordable source of energy for cooking, lighting, and heating.

How fast does kerosene explode like gasoline?

Kerosene burns relatively cleanly and has a low carbon monoxide risk – and due to its lack of fuel vapour, it cannot explode or cause a fire. However, the oil gives off fumes and inhaling a subsequent amount of kerosene fumes can cause dizziness – and long-term could cause neurological or kidney damage.