2 Stroke Fuel Oil Mix Calculator
Use the free Ken OConnor Racing 2 stroke fuel oil mix calculator to determine exactly how much two-stroke oil to add to your gasoline. Enter your fuel amount, select U.S. gallons, Imperial gallons or liters, and choose the recommended premix ratio for your engine.
The calculator instantly displays the required oil in U.S. fluid ounces, Imperial fluid ounces, milliliters and liters.
Two-Stroke Fuel & Oil Mix Calculator
Enter your fuel amount and premix ratio. The calculator converts the required oil into metric and imperial measurements.
Mix 4.00 U.S. fl oz (118.3 mL) of oil with 1 U.S. gallon of fuel for a 32:1 ratio.
Quick Reference — Oil per 1 U.S. Gallon
Important: Follow the oil ratio specified by your engine builder or manufacturer. Measure oil accurately and mix thoroughly before fueling.
How to Use the 2-Stroke Oil Mix Calculator
Using the calculator is simple:
- Enter the amount of gasoline you want to mix.
- Select U.S. gallons, Imperial gallons or liters.
- Choose the required fuel-to-oil ratio.
- Add the displayed amount of two-stroke oil to your gasoline.
- Mix the fuel and oil thoroughly before filling the fuel tank.
For example, a 32:1 fuel mixture requires 4 U.S. fluid ounces of two-stroke oil for every U.S. gallon of gasoline.
Always use the premix ratio recommended by your engine manufacturer or engine builder. Adding too little oil can cause accelerated wear, overheating or serious engine damage. Adding more oil than required can also affect jetting, combustion and engine performance.
Two-Stroke Fuel and Oil Mixing Chart
The following chart shows the amount of oil required for one U.S. gallon of gasoline.
| Fuel-to-Oil Ratio | Oil per U.S. Gallon | Oil per Liter of Fuel |
|---|---|---|
| 16:1 | 8.00 U.S. fl oz | 62.5 mL |
| 20:1 | 6.40 U.S. fl oz | 50.0 mL |
| 24:1 | 5.33 U.S. fl oz | 41.7 mL |
| 25:1 | 5.12 U.S. fl oz | 40.0 mL |
| 32:1 | 4.00 U.S. fl oz | 31.25 mL |
| 40:1 | 3.20 U.S. fl oz | 25.0 mL |
| 50:1 | 2.56 U.S. fl oz | 20.0 mL |
| 60:1 | 2.13 U.S. fl oz | 16.7 mL |
These figures apply to U.S. gallons. An Imperial gallon is larger than a U.S. gallon, so it requires more oil at the same ratio. Use the calculator above whenever you are working with Imperial gallons.
What Does a Two-Stroke Mix Ratio Mean?
A two-stroke fuel ratio compares the amount of gasoline to the amount of oil in the mixture.
A 32:1 ratio means the mixture contains 32 equal parts gasoline for every one part of two-stroke oil. A 50:1 ratio contains 50 parts gasoline for every one part of oil.
A lower first number means the mixture contains more oil. Therefore, 20:1 contains more oil than 32:1, and 32:1 contains more oil than 50:1.
The correct ratio depends on the engine, oil, operating conditions, engine modifications and the engine builder’s recommendations.
U.S. Gallons, Imperial Gallons and Liters
It is important to select the correct measurement system when mixing two-stroke fuel.
- One U.S. gallon equals approximately 3.785 liters.
- One Imperial gallon equals approximately 4.546 liters.
- One U.S. fluid ounce equals approximately 29.57 milliliters.
- One Imperial fluid ounce equals approximately 28.41 milliliters.
Because an Imperial gallon contains more fuel than a U.S. gallon, the two measurements should never be treated as interchangeable. The KOR calculator automatically performs the correct conversion for the selected unit.
How Much Oil Is Needed for a 32:1 Mixture?
For a 32:1 premix ratio, add:
- 4 U.S. fluid ounces of oil to 1 U.S. gallon of gasoline
- 8 U.S. fluid ounces of oil to 2 U.S. gallons of gasoline
- 20 U.S. fluid ounces of oil to 5 U.S. gallons of gasoline
- 31.25 milliliters of oil to 1 liter of gasoline
- 156.25 milliliters of oil to 5 liters of gasoline
You can enter any fuel amount into the calculator instead of estimating or rounding the required oil.
Tips for Mixing Two-Stroke Fuel
Use fresh gasoline from a clean fuel container. Measure the oil with a graduated measuring cup or another container marked in ounces and milliliters.
Pour approximately half the gasoline into the container, add the measured oil and agitate the container to begin mixing. Add the remaining gasoline and mix it again before filling the machine.
Use a high-quality two-stroke oil intended for the engine’s application. Do not substitute ordinary motor oil. Fuel that has been sitting for an extended period may lose volatility, absorb moisture or begin to separate.
Clearly label every premix container with the fuel ratio and the date it was mixed.
Frequently Asked Questions
Is 32:1 exactly 4 ounces per gallon?
Yes. A U.S. gallon contains 128 U.S. fluid ounces. Dividing 128 by 32 gives exactly 4 fluid ounces of oil per U.S. gallon of gasoline.
How much oil do I add for a 40:1 mixture?
Add 3.2 U.S. fluid ounces of two-stroke oil to one U.S. gallon of gasoline. For five liters of gasoline, add 125 milliliters of oil.
How much oil do I add for a 50:1 mixture?
Add 2.56 U.S. fluid ounces of oil to one U.S. gallon of gasoline. In metric measurements, add 20 milliliters of oil for every liter of gasoline.
Can I use a richer oil mixture for extra protection?
More oil is not automatically better. Changing the oil ratio can affect the amount of gasoline passing through the carburetor and may change the engine’s effective jetting. Follow the ratio recommended for your engine and operating conditions.
Does this calculator work for Yamaha Blasters?
Yes. This calculator can be used for Yamaha Blasters and other premix two-stroke ATV, dirt bike, motorcycle, kart, snowmobile, personal watercraft and small-engine applications. Use the ratio recommended for your particular engine and build.
Two-Stroke Engine Parts and Machine Shop Services
Ken OConnor Racing provides professional two-stroke engine machining, cylinder boring, cylinder honing, crankshaft rebuilding, cylinder head work, porting and complete engine rebuilding services.
KOR is also home to The Blaster Store, offering Yamaha Blaster engine parts, performance components, specialty tools and hard-to-find replacement parts.