Calculating 50:1, 40:1, and 32:1 Gasoline and Oil Mix Ratios for Two-Stroke Engines

Two-stroke engines are commonly used in various applications such as chainsaws, trimmers, and dirt bikes. These engines require specific mixtures of gasoline and oil for proper lubrication and combustion. In this article, we’ll guide you through the calculations for different gallon and liter sizes at three popular mix ratios: 50:1, 40:1, and 32:1. We’ll also provide a helpful chart for quick reference.

Why Are the Right Mix Ratios Important?

Using the correct gasoline and oil mix ratios is crucial for optimal performance and longevity of your two-stroke engine. The wrong ratio can lead to issues such as fouled spark plugs, excessive smoke, or engine damage due to inadequate lubrication. Different engines may have specific requirements, making it important to know how to mix the ratios properly.

Calculating Mix Ratios

To calculate the amount of oil needed for different mix ratios, you’ll need to know the volume of gasoline you’re using. Here’s the formula for the three mix ratios:

Amount of Oil (in milliliters) = Volume of Gasoline (in liters) * 1000 / Ratio

Amount of Oil (in ounces) = Volume of Gasoline (in ounces) / Ratio

Let’s create a chart to demonstrate these calculations for various gallon and liter sizes:

For metric units:

Gas (L) 50:1 Oil (mL) 40:1 Oil (mL) 32:1 Oil (mL)
1 Liter 20 3.2 4
2 Liters 40 6.4 8
3 Liters 60 9.6 12

For US units:

Gas (gal) 50:1 Oil (fl oz) 40:1 Oil (fl oz) 32:1 Oil (fl oz)
1 Gallon 2.6 3.2 4
2 Gallons 5.1 6.4 8
3 Gallons 7.7 9.6 12

Using the Chart

Refer to the chart above to quickly determine the amount of oil needed for different gallon and liter sizes at the specified mix ratios. Adjust the calculations accordingly if you’re using a different mix ratio. Use an interactive premix chart tool to simplify your calculations effortlessly.

Using a Calculator

For quick and accurate calculations, you can use a premix calculator. Simply input the volume of gasoline, and the calculator will provide you with the corresponding amount of oil needed for the 50:1, 40:1, or 32:1 mix ratio. This eliminates the need for manual calculations and ensures precise measurements.


Calculating the right gasoline and oil mix ratios is essential for maintaining your two-stroke engine’s health and performance. By using the provided chart and calculations, you can ensure that you’re adding the correct amount of oil to your fuel mixture. Always follow the manufacturer’s recommendations for your specific engine and conditions to achieve the best results.

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