Best Fuel Stabilizers for Long-Term Storage
Storing and stockpiling fuel is smart, but letting your gas go bad isn’t. Fuel stabilizer is proven to make a difference, and the best fuel stabilizers prevent fuel from separating, gumming, and varnishing your engines. Keeping your gas refinery fresh is possible with optimal storage conditions and the right additive. There are many types and brands of fuel treatment out there with varying effectiveness.
This is where we come in. We’ve researched the best fuel stabilizers, compared them specifically for generators and gas storage, and now the results are in: the overall best, a budget option, and a versatile option. If you need stable fuel, one of our picks will keep your stockpile in prime condition.
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In this latest update of the best fuel stabilizer, pricing has been adjusted, and more pictures have been added. When you buy through our links, we may earn a commission. Disclosure»
Best Fuel Stabilizer
PRI-G Gasoline Treatment
Versatile, Protective, and Restorative
Improve power, fuel efficiency, and store fuel refinery-fresh for years on end with the best gas treatment available.
*Price at time of publishing; check for price changes or sales.
Also available to buy at Walmart.
Less does more when it comes to Power Research Inc. (PRI) products. This bottle will treat a whopping 256 gallons, extending the storage life of a huge amount of gas. So, even though it is pricey, you can make it last, and it’ll end up costing the least amount per gallon of gas treated.
Specifications
- Application: Gasoline, gas/oil mixes, and ethanol blends
- Size: 16-ounce (also available in 32-oz, 128-oz sizes)
- Fuel Treatment: 256 gallons
- Fuel Added Shelf Life: 3 Years
- Stabilizer Shelf Life: Unlimited (3 years after opening)
You can also use PRI-G to top off existing, aged, and previously treated gasoline storage.
One downside is that the smallest size available is 16 ounces, so no matter what, you’ll need to spend over $20 to get a hold of PRI-G- even if you aren’t treating a large amount of gas. The larger bottles significantly reduce the cost per ounce as well, so they are worth investing in if you have a lot of gas to treat.
If you are looking for the best gas treatment available, grab PRI-G Gasoline Treatment.
Budget Fuel Stabilizer
STA-BIL Storage
Inexpensive, Effective, and Trusted
The big name in the game gets it done reliably and is the trusted budget option widely available.
*Price at time of publishing; check for price changes or sales.
Also available to buy at Walmart.
Sta-Bil has been treating fuel for a while and has a huge product selection. It’s available at every vehicle repair shop, automotive department, and several online outlets. The bottle keeps it simple and has an integrated measuring device to pour the right amount into your gas storage container.
Specifications
- Application: Gasoline, gas/oil mixes, and ethanol blends
- Size: 8-ounce (also available in 4oz – 128oz bottles)
- Fuel Treatment: 20 gallons
- Fuel Added Shelf Life: 2 Years (1-year if ethanol fuel)
- Stabilizer Shelf Life: Unlimited (2 years after opening)
People have been using STA-BIL for years across a wide range of industries and applications, so just because it’s cheap doesn’t mean it’s less effective. Our team goes back and forth in the red vs blue debate- blue being Sta-Bil Marine and red being Sta-Bil Storage. Both remove water from fuel storage, but blue has better treatment efficiency, treating 10 gallons per ounce. But red is half the price and increases the treated fuel life longer than blue by one year.
This means that they are virtually the same cost-efficiency. But Sta-Bil storage is available in smaller bottles at lower prices, so it ended up winning the red vs. blue debate.
If you are looking for an inexpensive but trusted option, STA-BIL Storage Fuel Stabilizer is what you need.
Versatile Fuel Stabilizer
Sea Foam
Effective, Versatile, and Reliable
Insanely versatile and trusted for a wide range of fuel types and applications.
*Price at time of publishing; check for price changes or sales.
Also available to buy at Amazon.
Everyone recognizes the versatility of Sea Foam. Besides bringing stubborn engines back to life, one of its many talents is as a fuel stabilizer. Not only that, but it’ll help drastically improve the shelf life of nearly any type of fuel.
Specifications
- Application: Gasoline, gas/oil mixes, ethanol blends, and diesel
- Size: 16-ounce
- Fuel Treatment: 16 gallons
- Fuel Added Shelf Life: 2 Years
- Stabilizer Shelf Life: Unlimited (2 years after opening)
Sea Foam is immensely versatile- you can use it to clean, lube, stabilize, and more. It’s easy to stockpile with its unlimited shelf life, and it works with almost every type of liquid fuel, ranging from heavy ethanol gas to diesel. It’s ideal for keeping on hand in car kits and inside your vehicle because of its versatility- you don’t have to keep it limited to the garage.
The one drawback is that it doesn’t treat a large number of gallons- if you are storing a serious amount of gasoline, you’ll want to look elsewhere. But other than that, the versatility Sea Foam provides just can’t be matched and makes it ideal to have on hand for uncertain scenarios or just everyday use.
It’s reliable, effective, and does nearly everything, so it’s easy to see why Sea Foam Motor Treatment is the versatile pick.
Diesel Fuel Stabilizer
PRI-D Diesel Treatment
Versatile, Protective, and Restorative
Improve power, fuel efficiency, and store fuel refinery-fresh for years on end with the best gas treatment available.
*Price at time of publishing; check for price changes or sales.
Also available to buy at Walmart.
PRI also gets it done with diesel fuel. It treats the same amount of fuel and lengthens the life in the same way the gas formula does. It can restore degraded fuel and lessen diesel smoke and soot.
Specifications
- Application: Diesel fuel
- Size: 16-ounce (also available in 32oz and 128oz jugs)
- Fuel Treatment: 256 gallons
- Fuel Added Shelf Life: 3 Years
- Stabilizer Shelf Life: Unlimited (3 years after opening)
PRI-D (made specifically for diesel) provides the maximum level of protection and reliability and is the best option to trust for compression equipment.
One drawback is that the PRI-G and PRI-D bottles and labels look very similar, except for the D/G letter and the color of the fluid. So if you have both on hand, make sure you grab the right one to treat diesel and don’t mix the two up.
If you are looking for the best diesel treatment available, grab PRI-D Diesel Treatment.
Comparison Table
| Fuel Stabilizer | Recommendation | Price* | Size | Fuel Per Ounce | Best Feature |
|---|---|---|---|---|---|
| Pri-G | Best Overall | $34 | 16 oz | 16 gallons | Added shelf life |
| Sta-Bil Storage | Best for Budgets | $6 | 8 oz | 2.5 gallons | Availability |
| Sea Foam | Best for Versatility | $10 | 16 oz | 1 gallon | Range of application |
| Pri-D | Best for Diesel Fuel | $29 | 16oz | 16 gallons | Compression treatment |
| STP Gas Treatment | $8 | 12 oz | 2 gallons | Inexpensive | |
| Lucas Oil Safeguard | $11 | 16 oz | 5 gallons | Ethanol treatment | |
| Sta-Bil 360 Ethanol | $17 | 10 oz | 5 gallons | Ethanol treatment | |
| Yamaha Yamalube | $17 | 32 oz | 3 gallons | E10 treatment | |
| Sta-Bil In-Season | $18 | 32 oz | 5 gallons | Treatment efficiency | |
| Howes Meaner Kleaner | $19 | 32 oz | 10 gallons | IDX4 cleaner | |
| Sta-Bil Diesel | $23 | 32 oz | 10 gallons | Compression treatment | |
| K-100 MG | $24 | 32 oz | 2.5 gallons | Water removal | |
| Sta-Bil 360 Marine | $24 | 32 oz | 10 gallons | Water removal | |
| Star Brite Star Tron | $28 | 32 oz | 16 gallons | Treatment volume | |
| Quicksilver Quickstor | $31 | 32 oz | 5 gallons | Reputation | |
| Fuel Medic Gas/Marine | $35 | 32 oz | 11 gallons | Water removal |
The Stabilizers We Tested
Our research narrowed the field down to several brands and types of stabilizers that we tested: STA-BIL, PRI, Star Brite, Seafoam, STP, Lucas, and more.
You can see our full list of review criteria below in the What to Look For section, with an explanation for each.
We also relied on studies conducted by the government and military for long-term effectiveness, since that can take half a decade to determine with fuel stabilizers. Those are listed in our Sources and References.
We’re always looking for new and better solutions, so if you have some fuel stabilizer that you swear by, let us know in the comments. We review most of our tested supplies annually, so we can try to get them in the next roundup and see if they will beat out our top picks.
Why Trust TruePrepper
I’ve been reviewing stabilizers for a few years now, and it’s great because I get to keep my own fuel storage fresh and ready for regular use and emergencies.
Hi, I’m Sean Gold, and I’ve been using fuel stabilizer in gas storage for several decades now. First using it to winterize lawnmower and 2-stroke gas as a teen, I went on to use it more often in the military in emergency generators and jerry cans.
I bought and tested all of these stabilizers in my own equipment and fuel storage containers (both steel and polymer). I ran the mixed fuel through a Honda 160CC small engine and a Toyota 3.5L V6 engine.
What to Look For
The best fuel stabilizer has a few features to look for:
- Value
- Effectiveness
- Ease of Use
- Shelf Life
- Versatility
When you get the right blend of these, you can find a treatment that will consistently keep gas at premium quality. Below, I break down what each of these features means for the gas stabilizers that truly set themselves apart.
Value: Cost vs. Benefit
The amount of money you spend on something like a gas treatment shouldn’t blow out your entire budget. You’re likely balancing a budget between that, gas storage containers, gas itself, and gas-powered equipment.
You never want to spend too much money on one thing when it comes to preparedness. It’s better to diversify your supplies and budget to make sure you are covered for a wide range of scenarios.
Effectiveness
First and foremost, you need to make sure the treatment you pick applies to the fuel type you’re storing. Fuel types commonly stored that can be treated include:
- Gasoline
- Gas/oil mixture (2-cycle)
- Gasoline (ethanol blend)
- Diesel
My versatile pick can tackle all of these, but fuel treatment formulated for specific fuels can be more cost-effective and last longer.
Solubility
Fuel stabilizer should easily blend in with gas, even when you add it on top. Typically, it’s best practice to put fuel stabilizer in the container first, then add the gas to mix- but that isn’t possible when you are trying to further your gas storage shelf life by adding even more treatment.
The solubility of a fuel stabilizer is somewhat related to its viscosity, but that isn’t always a surefire indicator. You can typically tell how well the stabilizer blends with fuel by the amount you are allowed to add. If you can continue to add fuel stabilizer over the storage of the fuel, then it is usually more soluble than other treatments.
It’s also important that the stabilizer prevents ethanol fuel from separating as well if you end up storing that.
Treatment Efficiency
The concentration and treatment efficiency of the fuel stabilizer set the mixture ratio. During testing, I encountered mixtures ranging from 1 ounce per gallon to 1 ounce per 16 gallons, which is a very large difference in the amount of treatment needed.
I evaluated the true cost of treated fuel, using the prices at the time of this review in the comparison table:
| Type | Cost* per Treated Gallon of Fuel |
|---|---|
| Sea Foam | $0.88 |
| Sta-Bil 360 Ethanol | $0.34 |
| STP Gas Treatment | $0.33 |
| K-100 MG | $0.30 |
| Quicksilver Quickstor | $0.19 |
| Yamaha Yamalube | $0.18 |
| Sta-Bil Storage | $0.16 |
| Lucas Oil Safeguard | $0.14 |
| Sta-Bil In-Season | $0.11 |
| Fuel Medic Gas/Marine | $0.10 |
| Sta-Bil 360 Marine | $0.08 |
| Sta-Bil Diesel | $0.07 |
| PRI-D | $0.07 |
| PRI-G | $0.07 |
| Howes Meaner Kleaner | $0.06 |
| Star Brite Star Tron | $0.05 |
You may notice that a few brands come in under PRI, but there is still one more difference: the added shelf life. PRI adds 50-200% more time to fuel shelf life than its competitors, making it ultimately more cost-efficient.
Shelf Life
Shelf life always matters because nobody likes to buy something just for it to expire and never get used. We considered both the unmixed shelf life of the fuel stabilizer itself, plus the added shelf life it gave the fuel it treated.
Unmixed
The de facto shelf life of fuel stabilizer in the original packaging is unlimited, so any fuel stabilizer that isn’t hitting that is missing the mark. All of my suggested fuel treatments have a limitless shelf life.
Mixed
Once you add a fuel stabilizer to the fuel, results can vary. Manufacturers list a 1-3 year shelf life extension of the fuel in ideal conditions. Here is how the treated shelf life looks by years added:
- Up to 1 Year: STP Gas Treatment, Sta-Bil 360 Ethanol, K-100 MG, Yamaha Yamalube, Lucas Oil Safeguard, Sta-Bil In-Season, Fuel Medic Gas/Marine, Sta-Bil Diesel, Howes Meaner Kleaner, Sea Foam
- 2 Years: Quicksilver Quickstor, Sta-Bil Storage, Star Brite Star Tron
- 3 Years: PRI-G, PRI-D
PRI and Sea Foam mention that they can be added to existing fuel storage on top of previous treatments. I’ve also used Sta-Bil to extend gasoline life well past the 1-2 year recommendation.
Ease of Use
Some fuel stabilizer bottles include an integrated measuring cup on the bottle. You can squeeze the bottle to fill it up to whichever amount you need and dump it into your fuel storage. This is great for measuring on the go, but it also takes longer to put large amounts of stabilizer into bigger fuel storage tanks.
Long necks on other bottles are great for dumping large amounts of stabilizer directly into a storage tank or fuel tank. The very small stabilizer bottles (4 ounces and below) usually have this design, since they are small enough to be dumped into a vehicle’s gas tank.
Versatility
Some fuel treatments do a lot more than stabilize fuel. The versatility of a fuel treatment ended up being the difference between some of our placements. Being able to use it for a wide range of engine needs can help in any situation.
How to Use Fuel Stabilizer
Fuel stabilizer is easy to use, but the suggested amounts to add can vary widely between brands. The optimal mix ratios are listed on the packaging, which usually makes it easy.
If you can, it is usually best to add the fuel stabilizer to your storage container or fuel tank before you add the gas. This way, pouring the gas will help agitate the mixture and blend the stabilizer more thoroughly.
With some types, that isn’t necessary, as you can add stabilizer to the ‘top’ of the gas to further improve shelf life. Those treatments are very soluble and blend well even without agitation.
Arch does a great job of demonstrating fuel stabilizer and walks through our budget pick in a Champion 7500 generator:
Who Needs Fuel Stabilizer?
Fuel stabilizer is almost a necessity for anyone storing fuel. Most people who store fuel are those with small engine tools, or boats, or are doing it for preparedness. For those with generators, it’s probably a mix of these, as you are using it in the generator itself and/or your accompanying fuel storage.
Besides regular use in your garage, stabilizer can be considered for these survival kits:
With unlimited shelf life on all of our suggestions, it never hurts to have extra on hand, either.
How We Review Products: We research thoroughly before selecting the best products to review. We have vast prepping and survival experience and bring in outside experts when needed. Hours on end are spent testing gear in stressful conditions and using specialized testing gear to verify claims. We assign performance criteria and impartially rate each tested item. Learn more about how we test.
Sources & References
All of our experience and the testing we do to determine the best fuel stabilizer are useless without listing our research sources and references. We leaned on these for the book knowledge that we paired with our hands-on testing and practical survival experience:
Frazier, R. (2009). Ethanol Gasoline Blends—Problems or Benefits for Customers? Energy Engineering. Volume 106. Issue 1. Pages 62 – 70. (Source)
Parker, G., et al. (2016). Two-Stroke Engine Cleanliness via a Fuel Additive. SAE Technical Paper. (Source)
Sluder, C., et al. (2022). Assessment of the Effectiveness of Three Aftermarket Gasoline Fuel Stabilizers in Preventing Gum Formation and Loss of Oxidation Stability. Oak Ridge National Lab. USDOE Office of Energy Efficiency and Renewable Energy (EERE). (Source)
Conclusion
Stabilizer is always needed for fuel storage, whether it’s for emergency storage, generators, or just your lawn tools. Using the best fuel stabilizer makes sense when you are relying on fuel for emergencies.
Here are a few other guides and reviews our subscribers have found helpful:
- Best Gas Cans for Prepping and Survival
- Best Portable Generators for Preppers
- Home Survival Kit List | 53 Essentials
See more of our expert-written guides, resources, and reviews in your search results – add TruePrepper as a preferred source.
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In reading this, to me, it remains unclear if you prefer the Sea Foam or the Pri-G. Is the latter an ‘upgrade’ from the SF and is the superior product? I’m not evaluating for automotive use, but rather a 4-cycle generator, but also would like a product suitable for 2-cycle lawn equipment that gives me the fits due to long periods of non-use. Thanks
Hi Ron, sorry the final verdict is convoluted. We’ll rewrite it to be more straightforward when we re-review in the spring. PRI-G is an upgrade over Sea Foam. We rated Sea Foam highly because of its versatility, but PRI will accomplish the main goal of keeping your fuel good to go much longer and with less cost.
After a couple of years storage with a stabalizer, do you need to replace the gas or can you just add fresh stabilizer for another couple of years of life?
You can add more stabilizer to extend.
Great article THANK YOU!!!!
I subscribed as a longtime prepper as my background in counterterrorism/ emergency mgt.
I have used Pri-G for at least a decade but seems to be much longer.
I use it in my snow blower, pressure washer, all gas purchased in 5 gallon cans, most of it used in my boats and jet skis I have had throughout the years.
Never a fuel issue EVER, which is an accomplishment with ethanol, etc. in gas at the pump.
My only question is STA-BIL 360 Marine Ethanol Fuel Treatment seems to have some great technology to include Vapor Corrosion Inhibitor (VCI)
I use 1/2 oz per 5 gallon can of the Pri- G as easier to measure and big believer more is not harmful.
My question is why STA-BIL 360 Marine Ethanol Fuel Treatment did not grab a top spot as it has always interested me.
Thanks for your research, it is appreciated
Mike
Hey Mike, thanks for the support! We’re actually split on the Blue vs. Red STA-BIL argument in our camp despite all the testing. Red won out as the ‘budget’ pick because it is so widely available and adds slightly more longevity to fuel, making it’s overall effectiveness cheaper for smaller fuel storage containers. While I use both Pri-G and STA-BIL Storage (red) in my containers, the most experienced guy on our team uses Marine (blue) in all of his- including yard equipment, boats, long-term storage, etc.
Aces IV