Two Cycle Oil Mix Calculator
US Gallons
Liters
16:1 (Old outboards/mowers)
25:1 (Heavy duty equipment)
32:1 (Classic motorcycles/saws)
40:1 (Common chainsaws/blowers)
50:1 (Most modern equipment)
100:1 (Specialty lean mixes)
To achieve a mix with of gas, add:
Always pour oil into the container first, then add gasoline to ensure a thorough mix.
Understanding Two-Cycle (2-Stroke) Engine Oil Mixes
Using the correct fuel-to-oil ratio is critical for the longevity and performance of 2-stroke engines. Unlike 4-stroke engines (like those in most cars) which have a separate oil reservoir, 2-stroke engines require oil to be pre-mixed with gasoline to lubricate internal components like the crankshaft, connecting rod, and cylinder walls.
Why the Correct Ratio Matters
If you use too little oil (a "lean" mix, like 100:1 when 40:1 is required), you risk metal-on-metal contact, overheating, and catastrophic engine failure. Conversely, if you use too much oil (a "rich" mix, like 25:1 when 50:1 is recommended), you will likely experience heavy smoke, spark plug fouling, and carbon buildup in the exhaust port.
Common Two-Cycle Ratios and Their Uses
- 50:1 Ratio: This is the standard for most modern outdoor power equipment produced by Stihl, Husqvarna, and Echo. It equals 2.6 ounces of oil per 1 gallon of gas.
- 40:1 Ratio: Common for slightly older equipment or high-performance smaller engines. It equals 3.2 ounces of oil per 1 gallon of gas.
- 32:1 Ratio: Often found in older vintage machinery or specific racing applications. It equals 4 ounces of oil per 1 gallon of gas.
How to Mix 2-Stroke Fuel Correcty
- Check the Manual: Always verify the manufacturer's recommended ratio. This is often printed directly on the gas cap of the equipment.
- Use Fresh Gasoline: Use 89 octane or higher. Avoid ethanol if possible, as it can degrade rubber components in small engines over time.
- Add Oil First: Pour the calculated amount of 2-cycle oil into a clean, approved fuel canister first.
- Add Gasoline: Fill the canister with the appropriate amount of gas. The force of the gas pouring in helps mix the oil.
- Agitate: Close the cap tightly and shake the canister gently to ensure a uniform mixture before refueling your equipment.
Standard Mixing Reference Table (US Gallons)
| Ratio | 1 Gallon Gas | 2 Gallons Gas | 5 Gallons Gas |
|---|---|---|---|
| 32:1 | 4.0 oz oil | 8.0 oz oil | 20.0 oz oil |
| 40:1 | 3.2 oz oil | 6.4 oz oil | 16.0 oz oil |
| 50:1 | 2.6 oz oil | 5.2 oz oil | 12.8 oz oil |