2-Stroke Oil & Gas Mixture Calculator
Calculate the exact amount of 2-cycle oil needed for your gasoline mix.
Required Oil Amount:
Mixing Tip: Always pour the oil into the container first, then add the gasoline. This ensures the oil mixes thoroughly with the fuel rather than settling at the bottom.
How to Use the Oil and Gas Mixture Calculator
Operating 2-stroke (or 2-cycle) engines requires a specific blend of gasoline and specialized oil. Unlike 4-stroke engines that have a dedicated oil reservoir, 2-stroke engines rely on oil mixed directly into the fuel to lubricate the cylinder, piston, and crankshaft.
Common 2-Stroke Ratios
The "Ratio" refers to the parts of gasoline relative to one part of oil. For example, a 50:1 ratio means for every 50 units of gas, you add 1 unit of oil.
- 50:1 Ratio: Common for modern Husqvarna and Stihl chainsaws or leaf blowers.
- 40:1 Ratio: Often used for smaller string trimmers and older equipment.
- 32:1 Ratio: Frequent in high-performance dirt bikes and older outboard motors.
The Math Behind the Calculation
To calculate the mixture manually, you divide the total amount of gas by the ratio number. Depending on your region, the units will differ:
Metric System (Liters to Milliliters):
(Gasoline in Liters / Ratio) × 1,000 = Oil in Milliliters (ml)
Example: 5 Liters at 50:1 → (5 / 50) * 1000 = 100ml of oil.
Imperial System (Gallons to Fluid Ounces):
(Gasoline in Gallons / Ratio) × 128 = Oil in Fluid Ounces (fl oz)
Example: 1 Gallon at 40:1 → (1 / 40) * 128 = 3.2 fl oz of oil.
Why Precision Matters
Using the wrong mixture can have severe consequences for your engine:
- Too little oil (Lean): Causes excessive heat and friction, which can "seize" the engine and cause permanent damage.
- Too much oil (Rich): Leads to "smoky" exhaust, carbon buildup on the spark plug (fouling), and reduced engine power.