Gas Oil Mix Ratio Calculator
Calculate the exact gas to oil mix ratio for your 2-stroke engine. Find out how much 2-stroke oil to mix per gallon or litre of fuel for chainsaws, weed eaters, and outboards.
Fuel & Engine Details
Enter your fuel amount and engine requirements to calculate the perfect mix
The total amount of gasoline you are mixing.
Select whether you are measuring in gallons or litres.
Check your engine’s manual for the manufacturer’s recommended ratio.
The fuel tank size of your chainsaw, weed eater, or outboard (in the same unit as above).
Mixing Instructions
Total 2-stroke oil needed for your fuel
Enter your fuel and engine details, then click Calculate Mix Ratio to get your exact measurements.
2-Stroke Fuel Mix Ratios
Understanding the correct dilution rates ensures proper engine lubrication without causing excess smoke or carbon buildup.
| Mix Ratio | Oil per 1 US Gallon | Oil per 1 Litre | Common Applications |
|---|---|---|---|
| 50:1 | 2.6 fl oz | 20 ml | Modern chainsaws, weed eaters |
| 40:1 | 3.2 fl oz | 25 ml | Some Poulan, Craftsman equipment |
| 32:1 | 4.0 fl oz | 31.25 ml | Older 2-stroke engines |
| 24:1 | 5.3 fl oz | 41.6 ml | Older outboards, heavy duty |
| 16:1 | 8.0 fl oz | 62.5 ml | Very old equipment, some scooters |
2-Stroke Engine Fuel FAQ
Everything you need to know about mixing, storing, and maintaining your 2-stroke engine fuel.
Most modern 2-stroke equipment (like chainsaws and weed eaters) requires a 50:1 gas to oil ratio. Older equipment may require 40:1, 32:1, or even 16:1. Always consult your engine’s owner manual for the exact manufacturer recommendation.
For a 50:1 ratio, you need to mix 2.6 fluid ounces (or approximately 77 ml) of 2-stroke oil with 1 US gallon of gasoline.
No, you should never use regular 4-stroke motor oil in a 2-stroke engine. 2-stroke engines require specific 2-stroke oil that is designed to burn cleanly with the gasoline. Regular motor oil will not burn properly, leading to heavy smoke, spark plug fouling, and severe engine damage.
Running a 2-stroke engine with too much oil can cause a smoky exhaust, fouled spark plugs, and carbon buildup in the engine. While it is generally less catastrophic than running it with too little oil, it will reduce performance and require more frequent maintenance.
Mixed 2-stroke fuel typically begins to degrade after 30 to 60 days due to the ethanol in the gasoline absorbing moisture and the oil breaking down. It is highly recommended to mix only what you need for the season and use a fuel stabilizer if you plan to store it for longer periods.