2 Stroke Gas and Oil Ratio Calculator

Instructions: Choose the units of fuel either gallons or liters. Input the amount of fuel, than choose which fuel to oil ratio you would like to compute, than click the calculate button. The answer will appear below the calculate button.

Units For Fuel: Gallons Liters
Amount of Fuel:
Gas and Oil Ratio:


(Answer will appear here)

Most 2 stroke engine's require the operator to mix oil with the fuel to lubricate the engine in just the right ratio to provide proper lubrication. There are a few exceptions, but not many. Some older 2 stroke motorcycles have oil injection, which means the engine has a pump that injects oil into the engine while the engine is running, and the oil is stored in a resevoir on the motorcycle. A properly calibrated injector pump injects just enough oil to provide proper engine lubrication. Now days the most common gas to oil ratio is 50:1 and 40:1. 50:1 is the most common, and it means there are 50 parts of gas to 1 part of oil. The operator must calculate how much oil to add to the fuel to obtain the correct gas to oil ratio. Over the years 2 stroke oil has improved and modern engines now require less oil to properly lubricate the engine. The manufacturer of an older 2 stroke engine might have recommended a gas to oil ratio of 16:1 or 32:1, but a similar engine today with better quality oil available and better engine technology can get away with mixing a ratio of 40:1 or even 50:1. If you have an older engine and you want to know the correct ratio of gas to oil, the best thing to do is go with what the manufacturer recommends. You might get away with using a higher ratio like 40:1 and 50:1 with a better quality oil, but why risk it. The internet provides a mountain of information on older engines, so even if you don't have a engine service manual you can almost always find the information online.

Things you should do:

  • Always use the manufacturer recommended oil in your engine. Never mix regular motor oil like 20W-50 in a 2 stroke engine.
  • Use the manufacturer recommended fuel in your engine, and use the correct fuel octane rating for your engine. Some older engines might require leaded fuel and some engines can't handle the alcohol additives added to modern fuels like E10. There are additives you can add to your fuel to solve these problems.
  • Make sure the oil is completely mixed with the fuel. Filling your gas container half way with fuel, than add the oil before filling the container the rest of the way helps to mix the gas and oil. After you add all the oil and gas to the container, shake it vigerously to help mix the gas and oil.