Two Ways to Calculate 2 Stroke Oil Mix Ratios
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There’s nothing worse than pulling your string trimmer to life, only to hear a sputter and cough. The culprit? A bad 2 stroke oil mix. And by then, the damage might already be done. Luckily, finding the right stroke mix ratio is easy. You’ve got two simple options: do it manually, scratching out your middle-school math on a scrap of paper, or use a 2-stroke oil mix calculator.
If you’re more hands-on, divide the total amount of unleaded petrol by the intended fuel mix ratio. For example, with a 50:1 gas ratio and a gallon of gas, you’ll need 2.6 fl oz of 2-Stroke engine oil. Keep a mixing bottle on hand to make measuring faster and more accurate.
But our oil mix calculator is by far a simpler solution over recalling Mrs. Klatt’s math formulas then double-checking, and it works two ways. Enter the amount of fuel you have, and it spits out how much oil to add. Or, if you’d like to use the whole bottle of oil for simplicity’s sake, enter that amount and it tells you how much fuel to add.
It really doesn’t get much easier.
Calculate: Metric, Imperial or US Gallons
Why the Correct 2 Stroke Oil Mix Matters for Engines
Two-stroke engines don’t have an internal oil reservoir like four-stroke engines do. That means the oil must be mixed directly with the fuel, usually unleaded fuel, to lubricate the engine. Using the wrong oil mixture can lead to poor combustion, fouled spark plugs, or even engine damage. With the correct ratio, your small engine runs cleaner, smoother, and lasts longer.
The Role of Oil Mixtures in Stroke Engines
What exactly does the oil mix do? It’s not just another additive Big Oil wants you to buy.
- The right 2 stroke fuel mix gives your two-cycle engine the lubrication it needs to perform at peak power during every power cycle.
- An improper fuel-oil ratio creates excess heat and friction. That can cause wear in the combustion chamber or lead to engine failure.
- Using high-quality 2-cycle engine oil helps reduce carbon buildup, keeping your internal combustion engine clean and firing as it should.
Applications of Two-Stroke Engines and Equipment
You’ll find stroke engines in tons of outdoor power equipment. Knowing the correct mixture of fuel is crucial no matter what tool you’re running.
- Chainsaws, string trimmers, and leaf blowers – Handheld equipment like this relies on a precise 2-stroke mix to avoid clogs and stalling, often in the range of a 25:1 to 50:1 ratio.
- Outboard engines, zero-turn mowers, and golf carts – Large or small, these machines count on a clean fuel mixture to keep moving. Some have fuel-to-oil ratios as low as 100:1.
- Power tools and other equipment – Any small engine without a separate oil system is probably using 2-stroke petrol and needs the correct oil/gas ratio, anywhere from a 16:1 to 100:1 mix ratio.
How to Calculate and Achieve the Ideal Stroke Mix Ratio
Fuel to Oil, or...
Oil to Fuel
Result
The most common approach to mixing fuel with oil is starting with a known amount of fuel—like 5 gallons—and adding the correct amount of oil to achieve a specific mix ratio.
Add Oil to Fuel
But it’s just as important to ask: “Since I only have 3 ounces of oil, how much mixed fuel can I make at a 40:1 ratio?”
This calculator helps you solve both questions—whether you're starting with fuel or oil.
Step by step | Fuel to Oil Mix Ratio Calculator
Calculate how much fuel to add to the oil or how much oil to add to the fuel, including specialized ratios like 300:1 for high-performance synthetic oils.
Understanding the Ratio of Fuel to Oil
Common fuel mix ratios include 50:1, 40:1, and 32:1. A 50:1 fuel-oil ratio means you’ll use 50 parts unleaded petrol to 1 part oil. If you’re mixing 2-stroke petrol for one litre of fuel at a 50:1 mix, that’s 20 mL of 2-stroke engine oil. For a gallon of fuel, you’ll need 2.6 fl oz.
Choosing the correct ratio helps your engine’s fuel tank function more efficiently, improves fuel burn, and avoids smoke and gunk buildup.
Using Tools to Mix Two-Stroke Fuel Properly
To get accurate results every time, use a fuel measuring container to make it easy to measure the right part oil for each liter or gallon of fuel. Combine your unleaded fuel with a premium two-stroke engine oil or synthetic blend, and shake it well.
Mixing by eye is not the move – too much oil can choke your engine, while too little oil can wreck it.
Two Stroke Oil Mix Chart
| SABER® Package Sizes | Mix Ratio | Gas Can Size | Mixing Notes | Product Code |
|---|---|---|---|---|
| 1.5 oz Pillow Pack | 100:1 | 1 U.S. Gallon | Pre-measured for 100:1 | ATPPK |
| 2.6 oz Bottle | 50:1 (or ½ for 100:1) | 1 U.S. Gallon | Use half for 100:1 mix | ATPTS |
| 3.5 oz Bottle | 100:1 | 2.5 U.S. Gallons | Pre-measured for 100:1 | ATPBA |
| 6.4 oz Bottle | 50:1 (or ½ for 100:1) | 2.5 U.S. Gallons | Use half for 100:1 mix | ATPSF |
| 8 oz Bottle | 80:1 | 5 U.S. Gallons | Pre-measured for 80:1 mix | ATPBC |
| 12.8 oz Bottle | 50:1 (or ½ for 100:1) | 5 U.S. Gallons | Use half for 100:1 mix | ATPTE |
| U.S. Measurements | |||
|---|---|---|---|
| Type | Mix Ratio | Oil | Fuel |
| Conventional | 32:1 | 4.0 oz. | 1 U.S. GAL |
| Conventional | 40:1 | 3.2 oz. | 1 U.S. GAL |
| Conventional | 50:1 | 2.6 oz. | 1 U.S. GAL |
| Conventional | 80:1 | 1.6 oz. | 1 U.S. GAL |
| SABER® Ratio™ | 100:1 | 1.3 oz. | 1 U.S. GAL |
| Metric Measurements | |||
| Type | Mix Ratio | Oil | Fuel |
| Conventional | 32:1 | 125 mL | 4 Litres |
| Conventional | 40:1 | 100 mL | 4 Litres |
| Conventional | 50:1 | 80 mL | 4 Litres |
| Conventional | 80:1 | 50 mL | 4 Litres |
| SABER® Ratio™ | 100:1 | 40 mL | 4 Litres |
SABER® ROFESSIONAL PROVIDES THE ADDITIONAL BENElT OF FUEL STABILIZATION helping prevent fuel deterioration during storage and protecting against poor engine performance.
There’s no need to add a separate stabilizer when preparing equipment for seasonal storage — SABER® Professional does it all.
Tips for Storing and Maintaining Your Fuel Mixture
First off, always label your gas cans. Otherwise, who knows if you’re dumping premixed fuel meant for your boat into your chainsaw, and it’s definitely not going to love that! And it just makes it simple to grab and go.
But keeping your machinery running well also depends on storage and maintenance.
Extending the Shelf Life of Two-Stroke Fuel
Two-stroke fuel doesn’t last forever. To keep your 2-stroke fuel mix fresh:
- Store it in a closed, clean container to prevent water or debris contamination.
- Keep it in a cool, dry place away from direct sunlight.
- Use it within 30 to 60 days – or at least within the season – to avoid fuel degradation that leads to clogs or engine problems.
How to Avoid Issues in Internal Combustion Engines
- Check your spark plugs regularly. Bad combustion can foul them fast.
- Keep the combustion chamber clean by using fresh fuel and a proper mix ratio.
- Never store fuel in the engine’s fuel tank for long periods.
- If your equipment has an internal oil reservoir, like an outboard boat motor, remove it at the end of the season to clean any settled material out.
Exploring Different Types of Stroke Engines and Fuel Ratios
Ever tried to find the dipstick on a 2-stroke engine? It’s a difference that makes you feel a little sheepish, but it’s only one of the differences between a 2- and 4-stroke.
Differences Between Two-Stroke and Four-Stroke Engines
Two-stroke engines burn a fuel mixture that contains both gas and oil, which means they require careful mixing before use.
Four-stroke engines, on the other hand, use separate oil and fuel systems with an oil reservoir, much like your car has an oil pan. It holds oil that’s used for lubrication, cooling, and to reduce internal friction.
While four-stroke engines have a longer shelf life for fuel because they aren’t mixed, two-strokes are lighter and more powerful for jobs you do by hand.
Choosing the Right Two-Stroke Engine Oil
There are a few options on the market. You could go with the traditional mineral oil, but then you’re dealing with the smoke, smell, and residue that gives 2-stroke machines a bad name. But hey, if you’re okay with extra maintenance and laundry, go for it.
The better solution is a synthetic 2-cycle engine oil that burns cleaner, almost as if it’s not a premix at all.
Products like AMSOIL HP Marine 100% Synthetic 2-Stroke Oil not only lubricate the cylinders but prevent deposits, protect against corrosion, and are safer for the environment than other options.
Choose based on your tool, how often you run it, and what the manufacturer recommends. Whether you’re running a two-stroke outboard or a leaf blower, AMSOIL has an option for you.
Start Perfecting Your 2 Stroke Oil Mix Today
Dialing in your perfect 2-stroke oil mix is simple. Use our calculator to quickly find your ideal oil ratio based on the fuel you have on hand – whether that’s a gallon of fuel, litres of petrol, or something in between – or based on the amount of oil you have.
When it’s time to stock up, shop Synthetic Lubricants for high-quality 2-stroke oil. We offer Free Shipping across Canada and the United States, so you can mix confidently and keep all your outdoor power equipment running like new.