How Long Does Gasoline Really Last?

Gasoline is one of those essentials that many preppers will choose to keep on hand as part of their survival stash. Considering it is absolutely essential for powering the vast majority of automobiles, smaller vehicles, generators and power tools this is prudent.

Unfortunately, gasoline presents several challenges for the preppers who would store it for the long haul, namely that it has a notoriously short shelf-life compared to other consumable resources in your inventory. How often do you need to rotate your gasoline? Is there anything you can do to extend the shelf-life? What factors affect its longevity?

gasoline Jerry can

Average gasoline you obtain from a gas pump will last anywhere from three to six months depending on its age and ethanol content. Higher ethanol content shortens lifespan, while purer gasoline will last longer. Other factors that can greatly degrade or extend the shelf life of gasoline are the conditions it is stored in, the container that holds it and any additives or contaminants that will improve shelf life, or reduce it respectively.

Understanding these many variables is absolutely essential for making sure your gasoline does not go bad leaving you stranded or out of power when you need it the most.

In the remainder of this article we will go over these variables so you are able to more accurately estimate the shelf life of your gas.

Understanding the Degradation of Gasoline

You can get a surprising amount of shelf life out of gasoline so long as you start with high quality gas, store it correctly and add a few select stabilizers and other chemicals that can boost its lifespan.

But you are right to worry about gasoline getting old or going bad, because over time it loses its combustive property through evaporation of volatile molecules, the infiltration of condensation (meaning water) and also through the separation of the gasoline and ethanol.

Contamination is an issue depending on how it is stored, and what kind of container it is stored in.


If you know any serious car guys, especially those who drive older, restored vehicles you have likely heard them railing about the addition of ethanol to gasoline. Ethanol is significantly corrosive, which leads to problems with certain engines, but it also reduces the shelf life of gasoline because ethanol readily oxidizes, ruining the gas.

To make matters worse, ethanol also attracts water readily which means any water that was already present in a container (to say nothing of humidity in the air) will contaminate the fuel with water.

As far as shelf-life is concerned, the more ethanol the gas has the shorter the shelf life, whereas little or no ethanol will greatly extend shelf-life.

Most of your common gasoline with ethanol added sold in the United States is what is known as E10, meaning it is 90% gasoline and 10% ethanol. This common blend will last about three months in a correct container stored in ideal conditions, but rarely longer.

Pay attention to the E-rating on your gasoline mixture because E15 or E20 will go bad even faster.

If you care to hunt down pure gasoline you’ll be happy to know that will last for about 6 months when stored under the same conditions. It will still fail due to oxidation in the end, but will do so much more slowly than ethanol-blended gas.

Also pure gasoline is hydrophobic, meaning it actively repels water and will not absorb it hungrily like ethanol blends will. It also does not separate like ethanol-blended gasoline does, making pure gasoline, if you can find it, your hands-down winner for long-term storage and stockpiling!

Storage Container

You always want to store gasoline in a proper container, and if you have any choice in the matter you will be wise to use a plastic gas can that preferably holds no more than 5 gallons.

I know, you can hate on those government-mandated complicated spouts all you want, but plastic has a lot of advantages over traditional and popular metal Jerry cans, namely it will not corrode internally ruining your store gasoline with particles of rust.

You should also make it a point to store your gasoline as near to container capacity as you can to reduce the ratio of gasoline to air volume, and slow condensation.

Where you store your can also makes a difference, as areas of high humidity or temperature changes will promote condensation over an area that is temperature stable.

Fuel Stabilizers

Fuel stabilizers are additives you mix into your gasoline prior to storage in order to slow down the oxidation process and prevent evaporation of those necessary combustive compounds that I mentioned.

Too much of either one and your gasoline will lose efficiency at best or just not work at worst. Lucky for us these fuel stabilizers really do work and are almost a necessity for efficient long-term storage.

Depending on the brand and its capabilities along with the grade of gasoline that you are storing, mixing in the right fuel stabilizer to your gasoline can extend your shelf life all the way up to three years!

That is rightly impressive, and something everyone should get familiar with especially if storing major quantities of gasoline is a significant part of your survival plan.

There are a few tricks for getting the most out of fuel stabilizer, namely it should only be added in precise ratios which means you’ll need to do accurate measuring of both your fuel and the stabilizer to ensure the mixture is proper.

Also it only works as advertised when added to new, fresh gasoline; adding it to old gasoline which is already too far gone will not result in any worthwhile improvement to shelf life.

Bring Old Gas Back to Life!

It is worth mentioning that you can bring old gasoline (only old, not contaminated!) back to life by mixing it in a 50/50 ratio with new, fresh gasoline.

The resulting mixture won’t work quite as well as fresh, new gas, but it will definitely get your motor turning assuming you don’t have some fussy highly tuned engine.

If you are sure the only thing wrong with your store gasoline is that it is well past its expiry date don’t be afraid to mix in some fresh gasoline if you want to recoup a little bit of your investment and avoid waste.

Before you get to mixing, make sure you give it the old eyeball analysis by pouring a little bit of the new gas into one clear container and a little bit of the old gas into another container. Then give it a look.

The old gas, if it is not contaminated, should appear only a little bit darker then the new gasoline. It should not appear cloudy, milk-like or have sediment or sludge floating in it.

Also, take great care when using this technique with ethanol blended gas; if you notice a distinct separation of layers in the gasoline, something akin to oil floating on water, your ethanol blend gas is no good because it has been contaminated by moisture. Throw it out!


Gasoline that is fresh out of the pump and stored properly will last anywhere between three months and six months depending on its ethanol content. Storage conditions, the nature of the storage container, and the presence of any fuel stabilizers can greatly decrease or increase this shelf life.

Make sure you understand the variables and eccentricities of storing gasoline if you plan on keeping any major quantity on hand.

12 thoughts on “How Long Does Gasoline Really Last?”

  1. About 6 years ago, our daughter lived in the city & decided she’d be better off w/out her car. So it was kept at our place. I added stabilizer to the gas. Every 2-4 weeks, I’d start it & let it idle in our driveway and/or drive it around our neighborhood, but never added gas to the tank. After 12 months, she returned, & her car ran fine. It was my first experience at maintaining gasoline for that long.
    I’ve read of preppers who keep some stored gas in a shed in cans, or in a tank, & use it in their vehicle(s) in 6 months/less – the idea is to have extra gas available if an emp hits.

  2. I have stored gasoline in 55 gal drums with STABL brand stabilizer for 3 years with no problems. I always add a little carb/fuel injector cleaner too.
    Are you aware you can purchase 100 octane gasoline at the Airport that not only does NOT have alcohol, but still has LEAD? Make sure you DON’T use it in vehicles with catalytic converters.

  3. I store gasoline in 55gal drums regularly for 5-6yrs using PRI-G. The BEST fuel preservative on the market. Stabil, I get about a year or so before it turns ‘varnishy’ smelling.

    We have a 300gal farm gasoline tank (and another of diesel)(both open vented) I get filled about once a year to 18 months from the local farm Co-op (they send a truck out). I’ll pump one or two of my oldest drums of gasoline in the tank before the truck gets here, he fills the tank, and my two drums (ethanol free gas), I put a dose of PRI in the drums and the tank, and put the drums back in storage. Not actually sure how long the drums would store, 6yrs is the oldest. I suspect they would go a LOT longer actually. Simply re-dose with PRI when pulling out of storage and they would be good.

  4. I’ve been keeping Stabilized Gasoline (Standard Pump Variety with Ethanol) for a number of years now and have had Zero problems using gas that is 2 1/2 years old in both vehicles and generators. Here is the methodology that I’ve been using (Not saying it’s the BEST, but it has worked for me):

    – I store in Standard Sealed 5 Gallon Containers. Make Sure your Containers positively Seal to avoid degredation / moisture intrusion from breathing.

    – Store fuel in as Controlled environment as Possible where they won’t pose a fire hazard to slow degradation.

    – I add about 1.5x the recommended amount of “Stabil”. I may not need to but I’ve had no problems with degradation or performance.

    – I always buy Premium (93 Octane) for storage. The way I look at it is that the Extra Octane level allows for longer storage while still remaining viable, and most generators etc. recommend it anyway.

    – If you use multiple containers Make a Tag with the date filled and Octane on it and Zip Tie it to the Handle. It’s very easy to forget to rotate your stock and only to find out that your reserve fuel is No good when you really need it.

    – For the Same reason if Possible Keep it in a location that you frequent with some regularity and can see those tags, it will help keep you on top of the game.

    – Oh, and ditto on the mixing non-viable gas with good as well. When I first started and before I started this methodology I had gas go south on me a couple of times and found that I could add 5 gallons of it to a 3/4 full tank on my vehicle with a 20 gallon tank was fine, just make sure you check for Contaminants and water before using it as losing $15 worth of Old Gas is still cheaper than an Auto Repair bill!

  5. I don’t know where this gas goes bad after 6 months information came from, but it’s being parroted to death (Oh Internet). As others stated, gas can last for many years as long as it’s stored reasonably well. As for the upper limit, who knows, but I’ve personally witnessed it stored for at least 6y and remain perfectly useful.
    I’ve got a can in the garage with 10% ethanol that’s over a year old for the mower, it runs just as well as when it was fresh out of the pump.

    • FYI, I had a 55 gal. drum of gas stored with Sta-Bil for TEN (10) YEARS, and it ran just fine in my minivan. Burned the whole barrel of 10 year old gas. It was just regular gas, no ethanol, in a tightly sealed drum, 98% full. Your mileage may vary. HIH.

  6. This question is for Dan. Was I supposed to sign up for a mailing list of some sort to be able thi access the weekly prep series on another site? I don’t know how to or where to do that. Please advise.

  7. Just before Y2K (the year 2000) I filled a couple of 55 gal. steel drums with reg. ethanol gasoline. I treated it with PRI-G (Petroleum Research Institute-Gasolene). After 7 years of grueling hot Southern temps. in a small metal storage shed, it performed well in an old Toyota. PRI-G, amazing stuff.

  8. I filled a 5 gallon red plastic gasoline container for my lawn mower 5 years ago from a Giant Eagle GETGO.. used no stabilizers and it still works fine – a bit of sputtering when it first starts then mower runs fine.
    Is it MAGIC GAS? Or like the Hanukkah story where a days worth of mennorah oil lasted 8 days?
    I still have 1 gallon left. Dont have a huge yard so a tank lasts all summer.

  9. We’re about to fill up a 500 gallon gas tank we just bought for the first time. It has the vents and all that. The hope was to add fuel stabilizer and then use it only when fuel prices are more expensive than our initial fill. So if prices drop, we’d fill up our truck and gas cans with cheaper gas and keep the 500 gallon fuel for when prices increase or fuel becomes harder to get.

    At this point I’m thinking we’ll get the best gas we can get, more expensive, and add the fuel stabilizer. Then count on two years of shelf life (we’re in Alaska).

    So we’ll buy other gas since it won’t be premium and just keep that premium gas in the tank. But when the non-premium gas prices rise above what we paid for the premium, we’ll start using that for our ATV, truck, and generators.

    The challenge is if we get to a point where we need to use the stored gas to make sure we use it all before it goes bad. Would be cool if there was a way to test it before filling up the truck or an ATV to make sure it’s good enough. We definitely got to get smart on that!


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