Gasoline stored in a gas can generally remains good for about 6 months to 1 year if kept in a clean, sealed, and dry container away from sunlight, heat, and ignition sources

. Without any additives, gasoline starts to degrade after about 3 to 6 months due to oxidation and evaporation, losing combustibility and potentially forming gum and sediment that can harm engines

. Using a fuel stabilizer additive can significantly extend gasoline's shelf life. With stabilizers like STA-BIL, gasoline can last up to 1 to 3 years under optimal storage conditions

. Proper storage involves airtight containers, cool and low-oxygen environments, and ideally filling containers completely to minimize oxygen exposure

. In summary:

• Without stabilizer: Gasoline lasts about 3 to 6 months in a sealed gas can.
• With stabilizer: Gasoline can last 1 to 3 years.
• Storage tips: Use airtight, approved containers; store in cool, dry, dark places; fill cans completely to reduce oxygen exposure; rotate fuel every year if possible.

After about a year, even with good storage, gasoline may lose potency and could damage modern engines if used without additives or treatment

. If gasoline smells sour or darkens in color, it is likely degraded and should not be used

. Thus, for typical gas cans, expect gasoline to be good for up to 6 months without stabilizer and up to 1-3 years with stabilizer under ideal conditions.